Viability: The game is playable! I'm able to move my player around and shoot easily.
Presentation: A bit confused on the goal at first but I got the hang of it eventually. I think the friction on the platforms needs to be just a touch more. While I like the challenge it can make the gameplay a bit annoying.
Theme: Simple theme. I think once you collect the coin it should be a different color in the UI below because if the player is surrounded by white it disappears.
Engagement: Fun platformer, I could see this expanding a lot very easily. Like mentioned in the Presentation- some tweaks to the friction or maybe that changes as you go through levels to increase difficulty? However, having it so slide-y in the beginning makes it kind of hard to get your footing.