Hey, loved your game, it was pretty fun overall, but here's some tips: Maybe add a timer to show when the next wave spawns, there were instances where I was getting some upgrades and enemies spawned right on top of me. Also, you gain points way too slowly on the beginning, and since the upgrades are very expensive some people could not play the game too much because of that. All the times I died, the game crashed on me, I don't know if it's intended. Finally the precision of the shots was very bad, I don't know if I missed a precision upgrade, but it could have some. Maybe also make the map larger, it could make dodging enemies easier, and would allow you to spawn more enemies in the long run.

The graphics were actually pretty good, all you need is some texture work and post processing, and maybe check the vertexes optimization, it couldn't hurt to double check.

Amazing work, hope to see the game finished!