Not fun. Made it to the store once and couldn't buy bullets for some reason? Tried a few more rounds, and it's just more of the same. There is one room which is absolutely impassible (the one that ends with a hard pit full of zombies), so it's really just compounded dicerolls to 1) don't get unlucky with that impassible room, 2) don't get unlucky with the stupid debris-shield mechanic, 3) don't get unlucky with bullets flying across the room leaving you helpless, 4) don't get unlucky being spawned into enemies, etc.
great graphics and audio, game design definitely needs more iteration.