Loved the concept! 

The speed of the combat is awesome, i love the megaman style.  I like how you have to dodge very quickly to survive.  

I think having a more noticeable queue when enemies are going to shoot would help.  The brown dust flying by covered up the particle effect of them charging up.  I couldn't figure out how to get to the upgrades menu or how to get my heat up.  Overall I really liked it, brought me back to playing on my gameboy advanced.

Very nice rhythm game