Loved the attention to detail on the main menu (e.g. volume slider) The name of the game is clever.  I'll parrot what other's said: At the start of the game you're posed to do what feels natural, and to me that was shooting my weapon at the mannequin. I shot at the manniquen but missed, and thought I did not miss. This to me felt like a bug. After repeated tries I eventually did hit. To me, I think you should increase the hitbox size of your bullets, so typical players don't miss if they really feel like they will hit. 

The same goes for the item on the ground. Missing the item while shooting at it lowers the quality of your game. Give your players a bit of room to register near misses as hits. If your hitbox must be this small, add a reticle so you can aim your gun accurately.

The mouse input instructions when attaching the gun are too dark. Consider adding a stroke to the iconography. I accidentally pressed "Ctrl+LMB" instead of "Ctrl+RMB" when attempting to move the camera, because of my old man eyes and brain.

Edit: As I see you have a laser attachment, I don't think you should add a reticle. I see why you made this design decision.

With the reticle attached I can guarantee that I'm hitting enemies, but my bullet doesn't make any reaction. Consider any simple or unique reaction to being shot, to add impact to this moment. Similarly, player gun knockback would feel natural too!

One time I was aiming so poorly because my mouse is centered in the game, but isn't the location of my firing shot, and that screwed with my brain.  I think that only happened because I'm alt tabbing? the mouse reticle is gone now.

I think you may want to scrap or delay the first challenge area where you are in a small shooting range. It doesn't provide the right kind of cover to let you win one on your opponents. It feels frustrating and I got my ass kicked 3 times. the enemy has way more distance on you so their cover is magnified and you go from having killed 1 enemy with no gun to getting blasted by 4 ai opponents. I think you need a bit of a warmup.

You need a visual indicator when items on the ground are able to be "picked up" and attached to your gun. Might be an okay idea to experiment with doing that to enemies as well tbh.     Okay nevermind, you just pick it up by walking overtop of it. FPS games have trained me to point at objects using my reticle to pick them up. That's what is natural to me.

It doesn't feel like having the laser beam helps. It would be nice to unlock this weapon after a moment of feeling difficulty not having it. I think enemies take too many hits, it's a bit of a slog. And their fire rate is just kicking my ass too. not so fun, and the bullets move fast enough that i cannot dodge them, which would lessen the burden of their OPness. I can't imagine getting past this part without losing half my health, a bit of frustration, and at least 2 or 3 enemies leaving the scene. Adding a crouch mechanic could help too but idk

I'm honestly frustrated getting mobbed by enemies in this little patch of the game trying to access the guns on the ground without dying. Letting your players not have to kill the first manniquen could help a bit.

Once I managed to mow down enough dudes and got to attach about 5 pieces I started feeling a serious rush of dopamine at the novel gameplay I was feeling, and the absurd choices I was forced to make. Wonderful.  If the guns were a bit more realistic and mock simulated the same splash damage / physics of the guns being shot, I can imagine this being a really funny game, and potentially fun multiplayer or single player game.

When I climbed the hill I was absolutely swamped with upgrades. I think the pacing of the game needs to be totally revamped so the increase is gradual and feels earned, and the dudes you mowed down on the way felt satisfying to kill.

It might be a good idea to tell the player what item they have picked up, so at least they can make a decision based on what it's function is. I don't know what one of my pickups is.

Sometimes pickup slots can swap rapidly between eachother. Sounds like a hard problem to solve but it reduces the quality of the game. There is probably a tried and true method for lego style building block type games.

Sometimes drops are inaccessible as they are too close to walls.

Sometimes the player character is rendered behind a wall which makes modification inaccessible.

The music rips so hard. lol.

Jumping on top of office tables is awkard. its like your jump height is just short enough to where it feels like maybe you;'re not supposed to jump on them.

wealking up stairs has a bug where you move slowly

some of the textures have a bug on the 2nd floor where they z fight

the rotating + sign items are a nice idea. I think some of the fun of this game could come from forcing players (by design and bad luck) to form odd combos that don't always work well. Accidentally shooting yourself with a rotating toaster gun sounds fun as heck.  As it stands right now it's mostly a power fantasy about smooshing guns together

There was one time that I successfully hit the enemy with a rotating gun and that was a great moment. Littering dozens of toast slices is awesome too I see the fan blows things around too.  The more integrated your mechanics are in big and little ways, the juicier this concept gets.

I reached the end of the game. Wonderful job team, this is a sublime game jam prototype. Y'all should be proud.