The Skull · 🖤🖤🖤🖤
Default head. No effect despite having many hearts which is great for discovering the game for a first time. No interest to use it once you start unlocking others.
The Block Head · 🖤🖤
Prevents you from losing your gear once hit. Instead of dropping everything, you will appear as a ghost and have a small-time to choose where to respawn.
The Heart Head · 🖤🖤🖤🖤🖤
The only Head with 5 hearts. It can be an option if you're having a hard time.
The Teddy Head · 🖤🖤
Allows you to jump 3 times in a row. It can be useful on big rooms or during the Dumb Computer level. It's also great against any boss.
The Dashing Head · 🖤🖤
Allows you to dash 3 times in a row. Might be the best option to beat the Gunless achievement. Long Zoomies Power-Up makes it hard to control.
The Floating Head · 🖤🖤🖤
Allows you to float after a jump if you keep pressing the jump button. Can be useful against a boss if you use it next to a weak point.
The Ammo Head · 🖤🖤
Increases your ammo capacity by 100% (doubles it). It's great, but I find it more reliable to play with more hearts and the XL Mags Power-Up.
The Gun Head · 🖤
The only Head with 1 heart. It decreases your ammo capacity by 20% and shoots an extra ammunition every time you use your gun. Also works with The Baseball Bat.
The Seeing Head · 🖤🖤🖤
Un-zoom your game so can see more the current level. Might be easier to spot secret areas. By the way, ditto, please add more secrets...
The Flying Head · 🖤🖤
Allows you to fly around. Works the same way as in the Dumb Squid level. It's really useful, but it's hard to aim while flying. It requires a lot of training.
The VVVVVV Head · 🖤🖤🖤
Changes the gravity when you jump, like in the game VVVVVV. Can be useful, but the mechanic is confusing and hard to master.
The Gravity Head · 🖤🖤🖤
Allows you to walk on every walls. I don't really get the point but why not.
The Ghost Head · 🖤🖤🖤
I have absolutely no clue what it does and have found absolutely nothing on the internet about it. Might be used to trigger a secret, I hope so.
As of January 2021, the Baseball Bat is kinda broken, since your can softlock any boss. If you start attacking a boss, your cooldown will infinitely reload itself. It's possible to kill it in a few seconds, especially with the More Ouch Power-Up. I need to try that technique a bit more, to know if that's 100% reliable. It should be the weapon used during speedruns in my opinion.
The Riffle · 40 ammo
First weapon the game gives you. It's a great rifle to start with, it has a great range and lots of ammo. The More Ouch Power-Up makes it even better. It requires to be precise with your shots. No need to farm chests, you can already beat the game with it.
The Flame Pusher · 30 ammo
Flamethrower with a poor range and low damage. It's alright with Power-Ups but requires to be always close to your enemies. It's decent during the Dumb Bird and the Dumb Head levels but not really against bosses. I rarely use it.
The Slugger · 15 ammo
Shotgun firing one big cartridge at the time. Does great damage but have very few ammunition. The XL Mags Power-Up will fix that problem. It has a surprisingly good range. It might not be the best weapon if your goal is to do huge combos.
The Shotgun · 17 ammo
Great shotgun that fires 4 cartridges. The spray is wide so it's easy to use and useful in many situations. Perfect when you're getting surrounded. I find it fun to have for the Dumb Squid level. Also works fine against Granny.
The Greande Launcher · 16 ammo
One of my favorite weapon. Does insane damage. It's not that easy to use since the grenades will fall quite rapidly. You have to pre-aim enemies often. It has the Boomers Power-Up effect by default. Great against every boss.
The Bubbler · 70 ammo
Weird weapon that launches huge inoffensive bubbles. The damage caused are meaningless, but it might be decent with the More Ouch Power-Up. They float, so you can't aim below you. Useless against any boss. I don't see the interest to use it.
The Squirter · 70 ammo
Water Gun that works a bit like the Grenade Launcher but with way less damage. A lot of ammunition by default so once against it might be great with the More Ouch Power-Up. That's all, I don't use it.
The Laser Rifle · 20 ammo
Might be the best weapon in the game. Does great damage and has a good range. It will go through everything, like brain blocks or crabs. It's useful against any boss, especially during the Head's and Bird's fights. The Bouncy Power-Up has no effect.
The Baseball Bat · 2 ammo
Successor of the Scythe from GoNNER. Great damage. It will refill itself after attacking or after a semi second. You will have to go play melee tho. Easy to use but hard to master.
Power-Ups will deeply affect your gameplay. None is useless, and it's up to you to find a great synergy with your Head and your Weapon. Some are nonetheless better than others, and so I always try to bring More Ouch, XL Mags, Long Zoomies and <3 with me.
<3 · adds one heart
Useful in any situation, especially using a head with low default hearts, like The Gun Head. If you loose it, you can always refill it, as long as you still have your backpack.
Free Stuff · 100% discount
Once at the shop, you can buy everything, for free. Not that useful, since you can unlock 5 Power-Ups as soon as you beat a boss [see "How to find Power-Ups ?"]. You will encounter chests often and buying hearts doesn't cost much.
Double Jumper · allows you to double jump
It can be useful during boss fights or during the Dumb Computer level, since it's easy to fall down. It's also perfect against Granny. Useless if you play with The Teddy Head.
Speedy · increases your speed
That one can be tricky to use in crowded rooms, but is a great one, especially against boss like the Dumb Bird, the Dumb Head and Granny. It might also help you to keep your combos, if you're aiming for that goal.
Long Zoomies · increases your dash
Allows you to dash for a longer time. It's efficient to escape a dodgy situation. Try not to dash-attack from too far or you might lose your invincibility and take a hit. Using that with The Dashing Head might be the way to beat the Gunless achievement ?
More Ouch · increases your damage
A must have. Always great. Just go get it. Any times. Combines with The Laser Rifle it's simply overpowered. I will try that combo to beat the Headless achievement.
XL Mags · multiplies your ammo capacity by 75%
It's really great with low ammo capacity weapons, like The Slugger, The Grenage Launcher or The Laser Rifle. It works also with The Baseball Bat. Handy against any boss or any room.
Bouncy · your shots will bounce off any surfaces
Perfect to clear a room or to beat the Dumb Head boss. It will make your game even more confusing tho. Bouncy doesn't work with The Laser Rifle.
Boomers · kills will result to an explosion
Like other Power-Ups, it's good against a room full off enemies. I also think it does more damage against bosses [needs confirmation]. The Grenade Launcher have that effect by default.