Really cool concept! It remined me of "Braid", but with a fixed timer instead of rewinding manually, and I think that's a creative take on the "countdown" theme.
It's obvious the game could have used a bit more visual polish, but I don't think that's a big issue here. The fun comes from the mechanics, and I think that was the right priority for a game jam.
The only thing I would mention is that, because the last level requires you to wait the full 10 seconds to have enough time to reach the exit, parts of the puzzle ended up feeling like downtime. One idea that came to mind would be to let the player adjust the rewind speed (for example, x2, x3 or x0.5). I'm not sure if that would actually improve the game, but it feels like it could open up some interesting possibilities.
Other than that, I would have loved to see a couple more levels to explore the mechanics in different ways. For a game jam, though I think it's a great entry. Good job!