Note that this feedback is based on the build(s) available at the end of the jam.
I really like the exploration of the jam's theme here. You've got 7 actions that you're expressing with two keys in ways that are possible to learn and master. I did find though, that the control layout and/or the level layout didn't lead to natural combinations of actions, and I can't help but feel that discarding the left/right move controls and having the left/right hop action triggered when holding down a direction would allow the game to flow better.
The time pressure provided by the rising lava might be a touch high, but I understand and appreciate the drive to create a challenging experience that requires many attempts and has more opportunity to stay in players' minds than an easy experience that a player will move on from and forget. In a larger game, this wouldn't be the right point on a difficulty curve to start at, but when there's only a single level, it's often best to focus on what represents what the game would be somewhere near its peak.
I had to give +x permissions to the game executable for this one. Typically, for Windows based developers, this is difficult to have control over, but if you're on Linux or MacOS, setting executable permissions with the "chmod" command on the game binary before zipping up the files will make sure that that's good to go on users' computers after they download and extract them.
Flopper didn't make my list of top favourites from the jam, but it was on my shortlist and was very hard to take off.
I spotted that you've continued to work on the game after the jam ended, and I'm looking forward to seeing what directions you're taking it in. Thanks for submitting and best of luck with continued development! :D