I really enjoyed this one. The mechanics were simple enough to understand that you didn't need to put any tutorial text to to figure out what things did. The twist in the middle where you could go backwards was a nice touch, but adjusting the music & having some strange dialog added an extra level of impact to it. What was even better was you realize that those "reverse" portals were in the original levels the whole time. I enjoyed it enough to play it through twice, which I usually don't do for game jam games :)