Viability:
• Game is playable from beginning to end! I wish it more clear, maybe just with some text describing the controls, and also to indicate that you've reached the end of what the game has to offer. All the elements are standard and work together, so it's easy to pick up!
Presentation:
• Outside of the game, the rules are understandable because you've said so separately. Inside the game, not quite. The elements are well-made, movement is easy and feels natural, albeit maybe a little too floaty, but I know that's the nature of the engine we're using!
Engagement:
• Having the theme (see below) will definitely help with engagement. I think the level design is successful, not too long, and the overall layout has good flow to it! Experimenting with scale (specifically making things bigger/giving more space) would be interesting.
Theme:
• Once again, outside of the game, the projected aesthetic is clear. Inside, not really. The experience would be enhanced greatly with some art, a defining aesthetic is necessary I think. In terms of theme, that doesn't really seem like it matters with the premise, which is fine but also depends on what your intention is.