A fantastic rendition of a classic genre
This is an amazing game. The amount of attention to detail in here is not something you see coming through the portal every day.
You've taken the genre of the space shooter (a la Galaga) and added most of the modern features gamers are now used to: weapon upgrades, bosses, save feature, a store, and even (the defining feature for me) a story mode!
The name of the game obviously comes from the art style choice. The result is a bit bizarre (in a good way!) and manages to convey the feeling of retrogaming pretty well. All enemies have their own behavior and some force you to think a little ahead when buying weapons.
Sound is a little repetitive, but this goes well with the game style. I would have also made the mouse button an alternative fire button - freeing up the keyboard for movement (some keyboards, like mine, have a hardware limitation on how many keys you can press at once). Minor things really... I have to look far to find any issue with this submission!
Verdict, two very enthusiastic thumbs up, and a 5 from me!