Nice graphics, sound and idea, but probably it has some design fails like the spawns position or the factors that increase with the dificulty curve.
In example, I would reposition the spawns near to walls to avoid the player to just run in circles. Also, increase the enemy health, movespeed (up to a cap), or just put a cap to the spawnrate because well... considering you can just kill 1 enemy/second and the spawn at a higher rate... this would kill your run everytime. 
FPS at the moment of the screenshot were <1
Despite all of that, it's a great game! Just with a few tweaks it can be awesome, keep it on!!