Platforming was simple but solid! I did find the insta-kill spikes in level 3 to be a bit frustrating, especially since after beating the level once I saw the challenge path and wanted to do it, but often times the spikes would kill me even if I successfully landed on the next block. I never made it to the end of that challenge, I gave up after falling through the one block gaps a few times :P
The idea of going back in time was cool, and the artwork to pull that off was also well done!
I definitely recommend adding some more sound effects and maybe some music. A little bit of sound design can go a very long way. I also highly recommend documenting the controls somewhere - even if it’s just on the itch.io page. I found them by trial and error but it’s good to know for sure that I’m not missing something
Kudos for providing a Linux build! :) 🐧