Very good gunplay gun models and enemy designs. Very floaty controls when jumping and strafing. I love the splash screen art.
Tip - do not use default Unity Screenshake effect for gun recoil - the camera should simply go up and spring back to position not just shake in all directions - this effect is only suitable for earthquakes or standing close to an explosion for example.
I hope that wave based arena gameplay is just for alpha testing and the game will have proper levels. I don't mind a horde mode survival mode as a bonus but these get really old if that's all what the game is.