Nice concept overall
The auto attack system is a nice change of pace but it has some issues though :/ The character doesn't seem to turn around properly sometimes, and this combined with the fact that you don't control exactly when you attack makes combat a bit tedious at times.
Other than that i like the general idea, the sorta horde mode and level up game mode you have here is fun and i feel that with the level up system this has a good base in place to add some future variety.
Artwise the pixel art is very nice, and the music is really awesome ^^
Regardless of the mentioned issues, you guys did great so keep at it :)