Man, add unlockables for full completion! Maybe speed runs, and a bonus challenge level, then a speed run for the bonus level after fully completing it.
Tight platforming action, good level design, smooth animation, solid control, great color palette and visuals, decent enemy variation and design. But the replay value is low.
This could make it into a full game on something like Humble or the various console arcades. But it would need more levels (perhaps different worlds/areas) and, as I said, more replay value, such as speed runs and a bonus challenge stage. I'd buy it for a few bucks. If you're feeling ambitious try 2-player head-to-head competition mode for points and time (I guess weight time into points, and give each enemy a point value).
3.5 because low replay value.