Hi, I've made a video about the game and I wanted to give you some feedback about it :D, hopefully it's useful to you :)
-The main mechanics and ideas of the puzzles are quite good and work well.-The difficulty on the levels is not balanced in one of them as there's one that feels very difficult in comparison with the others (the last one on the video).
-The "undo" mechanic works great and it's really useful, but I've found that if you press too many times the "undo key" it's likely to break the game if you press it too fast, and I mean break the game in a very literal way as it makes it go crazy and unplayeable until you restart the level.
-If you are planning on adding more levels they should be numered in order by their difficulty so players can know what to expect in terms of difficulty.
In conclusion, the idea is great and I hope you keep working on it. Hopefully this is useful for the development :D, also if you could subscribe that would help me a lot :)
Regards