Not a complete walkthrough, just a simple guide to answer a common new player question: What heroes should I focus on first?
Best Starting Characters Guide
In the late game you can make a specialized character for every tower; however, early to mid game, you will want to narrow your focus to fewer slightly more versatile characters. This list is what I would recommend as the first 4 heroes. The overall build strategy for this deck will be to place 1 EV wall, 1 gas trap, 1 explosive or inferno trap, and 1 strength drain aura in each lane to AOE clear small enemies. Then build a "tower stack" of Deadly Strike towers guarded by a reflect beam and buffed with an overclock beam to kill ogres and flyers. This general strategy can be adapted to include ensnare auras, flameburst towers, darkness traps, etc. as the map and DU allows.
Builder: Apprentice - Deadly Strike Tower, Flameburst Tower
This is your heavy hitting strong enemy killer and anti-air builder. DSTs are arguably the most versatile tower in the game right now, and find use in nearly every build out there. Flameburst Towers are not as universally adopted, but are extremely potent in the early game and maintain utility as AOE lane coverage in special circumstances later on.
- Range (most important stat early on to make Apprentice useful).
- Power/Rate (3-2 ratio optimized for Flameburst, 2-1 for DST).
- Any gear that has Range, Power, and Rate early on is sufficient, with fortify mostly being a comfort stat for the app towers if a stray enemy makes it to one.
Builder: Monk - Strength Drain Aura, Ensnare Aura
This is an important character specifically for his Strength Drain Aura (to remove immunities and help wall survivability) and, depending on the map, Ensnare Aura to help deal with kobolds. Lightning Aura is fun, but really doesn't shine until you have a specific monk dedicated to damage tower stats later on. Using the monk as a utility character lets you focus fewer stats in the early game which makes gearing easier.
- Fortify (More important in survival than campaign, but monk auras are notoriously fast-draining early on).
- Range (Bigger auras = easier to cover choke points).
- Power/Rate (Only required if you are interested in using the lightning aura early game, but I'd recommend using the DU on huntress traps instead until you have a dedicated lightning aura monk later on)
- Any gear that has at least Fortify and Range is useful for this monk.
Builder: Huntress - Poison Gas Trap, Explosive Trap/Inferno Trap, Darkness Trap
This is your AOE lane clearing builder with explosive and/or inferno traps, as well as your defensive utility builder (stunning lanes with poison gas and/or removing elemental immunities with darkness trap). Traps are not targetable by enemies, so they can't be killed unless you let them run out of charges, making them even more popular in the mid to late game when special enemy types become more threatening to your towers.
- Fortify (Same discussion as the monk above, traps are high maintenance until you have some fortify).
- Range (Same discussion as monk above).
- Any chance you have to trade Defense Rate for more Defense Power you should take it, especially with regard to Explosive Traps.
- Too much rate, early on, means your traps run out of charges quicker (which is the only way they can "die").
- It's better to do more damage at a slower rate (power > rate) until you have enough fortify to support more defense rate.
Builder: EV - Blocking Field (Wall), Reflect Beam, Overclock Beam
EV is a character you will definitely want multiple copies of later, but for the early game I recommend you start your EV out focused on building walls. I would argue EV's walls are more useful than the squire's due to their adaptive cost/health (longer walls cost more DU but have more health and vice versa) and you can often cover the same area that would normally require two squire walls with just a single EV wall, and for less overall DU cost. EV as your initial waller also means you have access to her reflect wall and overclock beams. Even if the overclock beam is not stat-optimized on your wall EV, it will still typically be the most effective use of the 4-6 DU you spend on them when placed in a tower stack buffing multiple defenses.
- Fortify (Most important stat for now, increase wall HP).
- Power (Of all of the other stats, this would be the most important one to look for (not to sacrifice Fortify) to improve your overclock beam).
- Range/Rate If your gear drops with these stats, great, they help your overclock.
- Not required early game.
- For stats, at least get Fort.
- Gear with 2 stats, look for Fort+Power. Anything else is just bonus at this stage.
First Specialist Characters
Once you reach level 70 on your first deck of 4 builders and get them some decent level 70 equipment, I would recommend taking a quick pause to level up a few specialist characters. Leveling really slows down in the 70s, so in the time it takes to get a few more levels on your original characters, you could have an entire roster of new characters level 70. Just build your favorite EXP map up using your existing builders, then swap out your new heroes to ride out the waves and get the exp. Here are what I consider to be the most important first specialist characters:
Active Character - Boost Monk
This is an extremely useful character, especially on maps where you can leverage a big stack of DSTs sitting on an overclock beam. Put a summit campaign pet on the monk that boosts defense rate and dump skill points/gear into "Skill" then stand on top of your pile of DSTs and drop your tower boost every 15 seconds. If you upgrade your weapon, put all of your points into the weapons elemental damage so you don't have to worry about the attack stat on this monk and you can still do decent damage. The main purpose is to boost a tower stack, though.
- Skill (increases potency of your tower boost skill).
- Vitality (stay alive when you need to run around and upgrade/repair or deal with random enemies.
- Casting (faster repairs/upgrades).
- There are some great guides for building an effective boost monk out there, so I'm not going into a ton of detail here.
Active Character - DPS Huntress (or, alternatively, another DPS hero of your choice)
Inevitably, you will find yourself on a map needing to kill a boss or deal with a tough lane where sitting on a boost monk isn't sufficient. A dedicated DPS character that you actively play to run around killing big enemies or a boss while repairing/upgrading is a huge boon to your repertoire. For this purpose I recommend you start with a DPS huntress, but EV is another solid choice, the Squire is popular (but less popular now than it used to be), and the Apprentice is good early/mid game (but has problems later on - although it can boost apprentice towers which makes it similar in capability to a boost monk to some degree).
- Attack (Increases your physical damage including melee or ranged damage, if you're focusing on elemental damage, this is not important, but for a DPS huntress you should prioritize attack and ranged damage).
- Vitality (You need this on a DPS hero otherwise you will spend all of your time just trying to survive).
- Agility (You need this stat total to be a total of 100 from gear or points to reach max speed, more than 100 does nothing).
- Casting (Repairs/Upgrades are faster).
- Skill/Boost (Whatever you get on your gear, but not the main priority.
Builder: EV - Overclock Beam
Time to separate your overclock beam from your waller EV. This allows you to keep 100% of your points spent in fortify on your waller, but prioritize power instead on your dedicated Overclock character.
- Power: All points here, all gear upgrades here.
- All stats are good for the overclock beam, but power will make the most difference.
In the end, you should end up with a roster that looks something like this:
- DST/Flameburst Apprentice
- Generic Aura Monk
- Generic Trap Huntress
- Waller EV
- Overclock EV
- Boost Monk
- DPS Hero of your choice (recommend huntress initially)
All told, using just the 7 characters here, I have been able to complete Nightmare Hardcore wave 25 survival on Glitter and make my way into Massacre. The new fusion/rift system obviously requires more intense specialization which I am not going to cover in this guide - but if you are a new player I would recommend progressing through the game without rift mode until you have a solid roster clearing NM or Massacre content before worrying about getting fusion sets and heavily specializing your team.
At this point, I would recommend you work on leveling towards 90 to unlock the ability to wear the best gear. By then, you should have an idea of what towers you're using the most, and work on creating heroes specialized in employing that tower and rapidly level/gear them using your core team.