Viability:
• I'm not sure if the game is playable until the end? There was a point where I got to the white rectangles that couldn't be shot down after I tried for a bit, I noticed that they're destroyed when enemies touch them. For the first couple of those white rectangle parts, I had to wait around for the enemy to show up and destroy that obstacle to make progress. That didn't work consistently, because it got to a point where there were no enemies around to follow the player and destroy the blockade. This sounds like a relatively easy fix though (I hope)!
Presentation:
• Unless I'm missing something about those white rectangles, then the rules are very straightforward! Moving around is easy, but backtracking to give yourself space to shoot the monsters was a little tricky though, since the direction the player faces is the direction they're moving in. I don't know how important it is for the movement to be oriented to the direction like that, since the game is always moving to the right, there really isn't a need to face the other way. That could just be a me-problem though.
* The kind of movement/direction controls I'm thinking of that fit here are the Classic Mode End Credit minigame from Smash Ultimate (maybe take a look?) The game moves exclusively in a single direction, it never turns around. And backtracking is still possible, maybe even easier.
Theme:
• Theme/aesthetic is very clear and very cool to look at! While the concept is simple, I think it's effective anyway because the emphasis is on the gameplay.
Engagement:
• I think the game is engaging, and your theme really helped capture my attention. The challenge was easy cuz you can hold the spacebar down to keep shooting, so if you positioned yourself correctly you don't need to worry about the enemies. However, I had fun doing that because it was funny when they didn't stand a chance >:)