That was great! The art is highly proficient, and the character design is exceedingly charming. The Contraesque mechanics are intuitive and a lot of fun. The soundtrack is superb. All-around, a great game!
While the audio balance is mostly fine, it seems that the "bullet hitting enemy" sound can stack on top of itself and peak the audio above +0.0 dB.
While the use of flashing is quite tasteful and subdued in its execution, the flashing objects might warrant a flashing lights warning.
Fantastic! Great work!