Very simple, yet addicting as hell. The sound design is very well done and optimization too i'd say, you HAVE to play with OpenGL tho.
At some point the normal enemies respawn becomes too low to be entertaining enough, because at +1hs you feel stuck, invincible and eventually bored.
END GAME (no spoilers, just a little help)
The game has an ending ya know, you need to get the 3 upgrades; both peer and drain need to be somewhere on the map... and then interact with one of them with bellow. How do below works? You have to use your whole mouse... After that just follow your instincts
This is my longest game in the fifth try or stmh, I thought I was god but I've already seen other comments too... I recorded some of it I'll update here if anyone's interested.