Great demo! A few things tho…
The first type of enemies need a better pathfinding because if you are above them, like in a ledge for example, they will run around below you instead of taking the stairs. Switching places, if you are below them, and they are above you, they should just jump down to get to you instead of taking the stairs. When they stop seeing you they behave weirdly, like they forgot where you just where a second ago. Sometimes you kill an enemy near them and they don’t notice.
The rest of the enemies (except the exploding meatball) are too static, it would be cool if they repositioned more often, or oven better, attack you while moving. Perhaps you can implement this behavior based on the difficulty, so instead of making the enemies tougher, they become smarter (or numerous!).
Having the option to change keybindings would be nice. Also, adding a “Select last used weapon” or a “Weapon wheel” would be very useful.
The double-barrel shotgun: did you put falloff damage in it? because I shot a meatball that was covering my whole crosshair (was at some distance from me) and it didn’t die. So maybe it was falloff damage or the spread of the crosshair isn’t big enough to be accurate. Also, nice touch on the reloading animation in the crosshair :D
Melee weapon: It would be fun if you could hit multiple enemies on one hit.
And that’s all I think, over all nice work.
I look forward to the complete game!