I love this. Lots of good design ideas that were executed well. The dash that's used for movement/defense/offense is brilliant. The shooting feels just right, the 3 shot burst is nice. The bosses were unique and not overwhelming.
I also have to say I absolutely love the art, and it's what made me wanna check out your game in particular. Getting some vibe of old DOS games from it (and I mean that in a good way!)
I can see myself playing a full version of this with more challenge.