Hi, first of all you used sound effects pretty eficiently in my opinion :) Visiuals were pretty good, i especially like those dropping things emit like when they are near ground.. cool! Theme was also well implemented but maybe you could make first character a bit slower because i was able to beat game with him and if i didn't play any further i would think "Theme is not implemented" but i defineately don't because i played game fully :)
My only complains are you can find "Safe spots" in map and wait in them forever. For example second wooden coloumn's left side is a safe spot and nothing can hit you. You can simply avoid this by makin 2 bullet shooters each side and makin them shoot faster. Also game freezes if i compleate 4 wawes which is unsatisyfing..
For a 3 day game it was super cool!