the particles and camera shake make killing enemies fun, the melee attack feels strong and satisfying.
I especially liked the zoom in effect when I dashed into an enemy. and the music was great.
the main game mechanic however, confuses me - I understand that the theme is paying the price, but killing enemies is the most fun part of the game, and this mechanic punishes me for it. the game was way more fun when I tried killing all the enemies then when I tried rushing through every single room, the upgrades also motivate me to kill enemies when they give me more damage. then why make me feel bad when killing them, you know?
solid game, good job.