Hi, this is a really fun little game which looks great and also incorporates the upside down mechanic really well! I think the artstyle really stood out for me. The platforms, character and the Xray effect really felt cohesive and the overall look was great - a nice sci fi vibe. Gameplay wise the puzzles were simple but fun. It taught the mechanics also quite well which was really nice. Flipping the spaceship around had a nice feel to it and given that this was the core mechanic, was really satisfying.
Given that you had less time to build it, the length of the game was perfect (better to do less things with more polish than have more content which is unpolished!). Some thing which i would improve on incase you decide to build this further - The movement of the character (left, right) could be tightened up a little - like after stopping to run it went slightly ahead and the acceleration felt a little sudden etc. But other than that this was really well made, and can be built on further adding new mechanics, more levels, etc. well done :)