Having actually eliminated the corruption from maps I can tell how to beat it.
Guide to Beat the Corruption
The first thing you want to do is start on Survival Island (bottom of the map). There is a few reasons for this. The main being that you get 2 free gates and 4 pre-built mana chargers (forget what they are actually called) on the map. This is critically important as it allows you to jump ahead in the early game and that is critical to win the first island and start you on your quest for total victory.
Place your castle somewhere in the middle of the island so you have easy access to the 2 bow towers, house and wood station. This is also important as reclaiming them will half the resources needed and give you a further boost at the start. Remove all the fence posts and wooden gate as you expand as they provide no help.
The first thing you want to do is set up 1 farm and spread your influence to the south so you can build a water purifier. As soon as the farm is up start collecting food.
After the food and water is set up claim the house and when possible the wood chopping structure.
Make sure to claim one bow station fairly early on (say by day 2 or 3) and build the structure that makes arrows.
When monsters spawn throw them in the gates (make sure to alternate so they can cool down) and save up enough mana to spawn 1 holy guard. When the night ends dispel him if he lives.
Congrats you have finished the easy part of the game.
After a few minutes you need to check the mini map to see where the monsters have spawned. This is where you want to start moving towards as soon as possible. You should be moving to cut off any expansion by no later than day 2 or 3.
As the monsters are really weak at this point you want to be expanding with critical buildings such as a stone mine, lumber mill and stone cutter. This should be followed by a crystal harvester and refinery.
Monsters will attack so summon a defender to slow them down and beat some off every night. They are still weak and some will go down to the defender. You should have both bow towers up and running so start throwing monsters between the 2 to have them shot to death. Also use the gates but be careful not to over load them as at this point you don't have enough magic to fix them easily.
During the day you should be using your hand to pick up and drop resources into the furthest building to speed up the building process. Use the 4 mana recharge stations to keep going as much as possible but before night comes make sure you have enough to summon a defender and pick up a few monsters. Collect mana from any monsters you throw into the gates to keep going during the night.
Surviving this part and the next is hard and takes some practice as you will have basically no defense or walls yet.
This is where you go from basic survival to containing the spread of the corruption. A few points I will add before I forget.
Make sure to build one dog house and if you see any wild dogs drop them near the dog house. Keep the dog house near your homes so they get a desirability bonus.
You should be upgrading structures and make sure to only build high capacity housing. You should be in a frantic race to build as much as possible as fast as possible. You should have 1 if not more farms going and if you have expanded enough build a land fill to start moving garbage. You should also be using the one building in the civics section that expands your building slots to allow you to build more. Also you should be upgrading your castle whenever possible as builders and organizers are the backbone for expanding.
So the idea is to somewhat predict and rope off the corruption. What is critical is that you can't let any slip through. Use your corruption resistance map to see what you have covered. As there will be lots of water it is hard to tell where exactly it is. Be safe and expand around it in a wide arc rather than be to close and have some escape. Don't waste time trying to get rid of the water to see where the corruption is located. The water is your friend as is slows monsters down and keeps fire elementals from attacking you.
You need to switch to large firepits at this point. You also need to be thinking about where you are going to have walls and where you will have an entrance into the village. You should be able to summon 2 defenders at this point and you want to start setting up 1-3 stone defenders and upgrading them as soon as possible.
I hate this part. Once you have the corruption roped in with fire pits you need to start building walls ASAP. Nothing else matters at this point as you need to start directing the flow of monsters. This is brutal as you will probably be in the water somewhere and need to make the land and then the fences so it is slow and difficult. You only have summer to complete this as if you wait to late ghost will start spawning and it is all over if you are not ready. We will talk about how fun winter is later.
In the prep (other than for winter) it is important that all walls have 1 tile of water beside them in a perfect circle around the corruption. If you do not have this when fire elementals spawn they will kill you. The water (if not frozen) stops them from crossing over to your side so this the best of walls and it means you only have to deal with them for the first winter. If you do not get rid of all the corruption by the second winter you will die so there is a very real time limit on getting this done.
You have 2 options for walls either start with cheap wood ones and then add multiple layers of the ghost blocking walls behind them or just start with the ones that block ghosts immediately.
You want to have a kill box set up for your main entrance. The fun part is if it is to long monsters go through walls and if it is to short you die. The spacing also matters. What you want to have is a N followed buy a U. If built correctly you should have a 10 tiles down and then 5 tiles to the right then 10 tiles up and then 5 tiles to the right followed by 10 more down. I hope you get the idea. This is just a little maze and the set up will make more sense when I talk about spells.
The other important point is the spacing. The monsters will hug one side of the walls and you will use lightning to zap them. If you pick right beside the wall you will damage it so you need a space away from the wall to cast the spell. You will need another space away for the other wall which means walls need to be separated by a minimum of 3 tiles or you will damage them.
You will want to make sure the walls are also 1 layer thick where the monsters come in. 2 layers thick when the turn the first corner happens and 3 layers thick closest to your base. All the rest of the base should be 3 layers if not more thick and make sure you can't shoot over them. This keeps fire elementals from sniping your buildings on the other side. The kill box should only use fence you can shoot over. Everywhere should only use walls that are ghost proof so they don't dig through. I will let you figure out where to place the fire pits to make this work.
Setting Up Shop
So you have your wall and a basic flood of defenders battling the monsters every night but your corruption is going to start spawning harder monsters soon. You should be into about fall by now? You next step is to set up a stronger magic network to support some elemental towers. Build 5-10 of them at just at the start of your villages side of the kill box. Upgrade them to ice as soon as possible.
Once this is done constantly start expanding everywhere on the map as quickly as possible. You need to have 100% corruption resistance coverage everywhere. Use fire pits to space out buildings and then remove the fire pit once the second building is done. Keep farms, houses and water tight to the castle but spread everything else out like crazy. Remember if you upgrade the civic building that lets you build organizers its range extends. Extra stone, crystal and wood gathering structures are awesome as they have huge range and provide faster processing and more storage. Get any building going that you are missing. Keep enough water to harvest but get rid of water where you are expanding as it affects building range. You should be able to cover the whole map with around 100 buildings.
Save migration stations and trading for the end game. They are useless in helping you survive and the range they provide is not really helpful and other structures extend your range more or provide better economy . Set up a few more gates for tossing monsters into close to your walls. Note that when monsters are high level they give you lots of mana and you will need it to survive.
Note: This is a place holder where I can add more details on how to set up trash, food or other items the community is struggling with. Post below if there is something you are not understanding on the set up and I can help. I do expect if you are playing on survival mode that you have the basics of how to manage your economy so am not covering this is detail).
Again help build as much as possible and forget summoning any defenders at this point. The towers and stone/wood/crystal defenders should be doing all the work. Make sure you have recall on hot key to keep any dumb villagers from running into monsters at night as they are still to few to risk losing. You better get use to using recall all night long as villagers love to run into the corruption and kill themselves and its only going to get worse.
This is the longest and hardest part. You need to survive and have almost all the map covered (other than the corruption) by the start of the second year. Double, triple even quintuple check your corruption resistance map to make sure everything is covered prior to trying to push the corruption back. The reason you want everything covered prior to pushing is to slow how powerful the monsters scale until your economy is as powerful as possible. You also need time for your population to grow to give yourself more mana for the crazy that is to come.
At this point you should have your castle close to max, over 200 villagers, something like 10 or more farms (don't bother with meat or kitchens until end game) and all max organizer buildings, fully upgraded. You should have defenders (all types) all over your side of the map. Make sure to only pick ice for everything. Picking fire anything will kill you as it has a chance to spawn fire elementals which will equal instant death later on. I don't know why poison is even a choice as it is useless. Lighting...if anyone has any comment let me know but it seems useless as well and will not help with the strategy I am outlining anyways.
This will take approximately 8 hours of real time to complete.
At some point the monster amounts and levels will start to overwhelm your defense. This is when it is time to switch the the end game strategy. First always have the game on x1 speed at night when the monsters start spawing. IF you are a pro gamer with the reflexes of a god and can handle x3 speed well feel free to ignore.
What you want to do is cast the cold spell in your kill box. If you set it up right monsters should get frozen going up one way, over and down the other. You want to layer this spell and be casting it always as fast as possible off cool down. If you miss this even for a bit the monsters can unfreeze and your dead as you will have hundreds captured at any one time.
If you set up your water correctly the fire elementals will leave you alone as they won't cross the water. You will have to deal with them one winter. Charm them where possible to help kill and delay others, throw them into your gates and zap them. Do whatever it takes to survive them and know they are always your first priority to kill because of the range and crazy damage they deal. After the first winter you only have one monster that does not freeze and is a pain!! I will talk about them in the next section.
At some point your going to say some really choice words when they kill you again and again. All your walls should be thick enough to keep them digging through so here is what you do.
I think Dark Souls (before the nerfs) taught us how gods deal with problems....lighting! This is your go to spell and thank the developer that this spell does not need to be click spammed or you would break your mouse button. Remember you just need to hold the button down to make this spell work.
Some important points to remember. Do not have lightning rods near your walls. If you do you will die and you deserve it.
Secondly once you are pushing into the corruption with large fire pits you can start to make god walls. What you want to do is try and make a tunnel using a fire pit (they can float through the fire but other monsters have to go the long way around) to separate them out from the rest of the mobs if possible. This lets you kill them before they get to your kill box. You may be thinking why don't I just zap everything in the kill box and problem solved? I would say to you good luck. In theory it is possible but with the amount of dead bodies, defenders crawling over everything, cold spell spam and floating mana particles you won't see what you need to and die. You will also eat a lot of lag and probably end up miss clicking and zapping your walls. Some of the stronger ghosts will also slip through to quickly and you will probably die.
So just draw some sort of a line to filter out the monsters from the ghosts. I will leave it to you to figure out how that looks on your map. Once the ghosts leave the god wall/funnel just hold the lightning down and kill literally hundreds of them every night. If a few slip through because you are recasting your cold spell you should have enough space to hunt them down and kill them before the next wave hits you.
When you get to this point cast recall around the kill box often to keep villagers from walking into the cold spell and freezing to death. I love how if you drop a monster into a gate is scares villagers from a full map away and any other spells cause them to stop and be confused but a huge AOE freezing spell.... nope got to run into it and die up close with the monsters.
So you should have been pushing into the corruption and have everything covered at this point... Oh wait I can read your mind... I hear you thinking that monsters are everywhere and over level 100 and run at the speed of light and can one shot anything, including your slow stupid villagers before they can deliver goods or build the fire pits?
Well yes that it a problem so this is where you as the god come in. What you want to do is have no builders or organizers in your tab so when you place a fire pit no workers are assigned to it. If anyone is assigned then if you pick up and drop wood onto the pit it won't register as it is already assigned to a worker who will deliver the resource. The added bonus is you know they will never get there as they will either die to monsters or be scared off, drop all the logs and then have the monsters take them to build structures. This is really annoying so be grateful that you only have to drop 10 wood per pit and only need to do this something like 20 times.
Once you have added the wood then cast the build spell and it should finish up. Again you need to be doing this as fast as you can and if you are not done by the end of the second spring you are probably dead and just don't know it yet.
Once you have full coverage you should only have about 300-400 corruption tiles left....
You should be sitting around 300-400 villagers and be ready for my favorite part. This is when you finally get to bully the AI and take some sweet sweet revenge!!
Be a Pest Be a Pest, Enjoy a Well Earned Rest
At this point every part of the map should be covered with corruption resistance so now what? I find the fastest way to remove corruption is to kill workers and buildings as it seems every time one has to be re spawned a tile of corruption has a chance to be removed. This only applies during the day and not the night when you kill close to 1000 monsters.
There is lots of ways to enjoy this but a few of my favorites are charming fire elemental and giving the AI a taste of its own medicine. They can 3-5 shot most AI buildings if left unchecked which is really satisfying to watch. Charming ghosts is also fun as they are hard to kill and make a mess.
While it is not effective I also like creating god towers just to annoy the AI. Even if you summon 8 at a time they will all be destroyed by a single monster but if you charm a few then the towers can add a bit of DPS and overall just be a pest. When destroyed they also create god dust which is valuable at the market. To bad it seems to be the only thing worth trading but meh.
So this should go on until almost the second winter. You may start to feel scared that you are not going to make it...but if you have done everything right you will get rid of everything with 1 or 2 days to spare. Fighting every night on x1 speed in the most tedious part.
I would say if you go into winter try your best to survive... If you want to try start making fire pits at your kill box entrance as you do not want a building to go down and then you lose the corruption coverage. On that note make should you also have ballistic towers and defender stations all over your side of the map for blood moons. They are the worst followed by meteor showers. The reason they are both so bad is every time a meteor hits it causes fire and has a chance to spawn a fire elemental. You MUST find and grab them almost instantly or even one of them will kill everything you have built in a single night. This is the worst at night when you are already busy killing monsters and trying not to die.
This next part some will consider cheating but hear me out. After you have put close to 20-30 hours getting to this point one slip up is instant death. How do you even practice surviving and what fun are you having just repeating the same map over and over? If you fail a few times and start from scratch you will also quickly see why this next comment is worth considering. The developer, in his infinite mercy, has allowed you to go back to a previous save state if you hold the shift key when selecting your starting map. If you make what you know is clearly a mistake I would suggest doing this so you can practice surviving a really hard night. This can save days of real life time just to get to this point again. If you do this or not its up to you but I think being able to have the equivalent of a quick save is fair if you consider that most modern games allow for this.
I Beat It!? Now What?
This is just the first map and you need to get ready for the next.
So what you want to do is mass build migration and courier stations. You should be able to mass move 300-400 people and transport 200 resources per day. Don't send anyone yet, we are just getting started.
Next you are going to start mass blessing all the mothers and getting god children going. Go to the child tab and if they are just a regular child...uhmm....
If you are an evil god you do need human sacrifice right? Isn't that why you got rid of the other god so you could do as you please?
If you are a good god think of it as you as sending children to a very special and magical place where they will be happy forever...
Either way drop the normal children into the gate as they are not needed. You should have around 450-500 housing capacity but probably don't want to build more at this point and add enough of everything to support your people.
You can also start dropping anyone that migrates into the village as they will all be normal. You may also want to consider some low level elders... just saying they all take up housing space....
Build the last of the useless buildings like clinics and animal farms and ranger stations because why not? You can get rid of fire pits to have more building slots but be careful to make sure you have a building with all the coverage considered so you don't spawn monsters. Also buildings can be attacked so make sure you have defense in place for blood moons.
Once you feel you have enough high level god villages (around 400 is when I am satisfied) then you want to plan a 1 day mass exodus of the entire village, and a modest amount of wood and stone for the first day. If you sent to much you won't be able to use it all and will make trash slimes so don't do that. Send 2 more days of supplies (second day lots of wood , stone and some board and cut stone) the 3rd day include high end resources (iron and refined crystal). Build like mad. Use the labor spell for added speed (you will have high mana from all the people) and go crazy.
Repeat the same strategy but this time crush the AI within the first year and make sure to rub it in.
From this point you will have multiple paths to branch to and a foot hold to always send resources to other locations. After having done this many times myself I usually just survive the 1 year and move on as total elimination on all maps could seriously take months or years of real time. If anyone has the patience to kill every map, wow! Let me know if there is a special end game state.