I really enjoyed this one. The graphics are music were great and I love that transition effect between screens. The screen shake and animation effects really add to the vibe of the game.
At first I didn't realize you had to shoot the enemies 3 times to kill them and I actually ended up mostly jumping on their heads because I found it more fun and sometimes easier. I wonder how it would feel if you had to shoot them twice or if that would be too easy.
I played this for probably half an hour and managed to get as far as the first boss, but sadly I did not beat it. Overall it is fairly challenging although after a while I could get the first 5 floors down pretty easily. However after that you introduce the enemies with guns and sometimes they can spawn and shoot within like 1 second and I usually lost my health to those guys. I was very happy to see the shop had a max health upgrade in it though.