Viability: I think your mechanics are in right place but can use some work with regards to placement. I feel like starting at the bottom would work better for the players control. I also think that spacing things out a little more will help me move around with more certainty.
Presentation: So far I can tell what I'm not supposed to hit, what I can hit, the background is cute and the level is pretty clear. The pool of water (as a danger) was a little confusing but that can be improved .
Theme: Seems like a simple platform shooter, more flavor will come as you add more style.
Engagement: I think the mechanics are fun, I just wish things were a little more spaced out so I had less chance of dying right now is all.