DemonNest

Survive all the waves (I think it's 20) because I haven't

 use power ups such as:

Shot Gun Mode (red)- turns gun into a shotgun for 3 seconds

Fire Rate Increase (blue/purple) - increases fire rate

Heal (green)- increases health by one (can't pick up if you're on full health)

Kill All (yellow) - kills all enemies 

controls- W,A,S,D to move, left click to shoot, use your cursor to aim

enemies: 

tiny purple guy, 10% chance to drop powerup, 2 health, normal speed

bulky orange guy, 40% chance for power up, slow- high damage

red shooter guy, 60% (or 80% I forgot) chance of power up drop, fast

Big big guy- Necromancer- 100% chance to drop power up,  slow- high damage

BUGS- 

- enemies do sometimes spawn on you (something with colliders

-if you collect the shotgun power up and after it's 3 seconds you collect another one you won't get the power up

-there's a bug you jump off the map (if it happens just close game and restart because you have to kill all enemies in order to win)

there's no pause

good luck