I love the sketches
Overall I thought this was great, I really liked the style the backgrounds had with those sketchy shadings and the same with the 'game over' screen and how Pico could pick up the bodies and use it as a shield. =)
The gameplay was quick to react and very simple. Pico's facial expression really lightened the mood for me and made it more enjoyable. The music was a good match because of it's high pace and 'alive' mood, and it simply sounds good too.
But just a few things I'd like to see IMO:
I would've liked to see the bullets travel after Pico shoots though. Like a little black dot that just flies across the screen and into the enemies chest would be so satisfying to see...
Also more blood. So maybe instead of blood only coming out after the enemies die have a little bit dramatically spray off with every shot? (specificaly the blue guys in the first few levels).
Anyway a great Pico Day submission, excellent work Bezman this turned out awesome. 4/5.