Thank you very much for the wonderful feedback, I think seeing people playing my creations is the coolest part of developing a game, but anyway, let's get started!
Regarding the keys, I really don't know why I chose not to put WASD, since it is something that you end up doing automatically in Unity, but I updated the game with them.
About the lava bugs (black border) and exit delay, they were fixed in the update as well: ^)
About Lava itself, it was literally the hardest thing to do in this game, because it is done in real time by shaders, and I am still learning it, it took me a long time to get it done, but the result satisfied me.
About the procedural generation of the scenario is done in a very simple way, it basically creates a grid of level +1 x level +1, that is, at level 1 the grid is 2x2, at level 2 is 3x3, and so on. In this grid, he chooses a random tile, and makes a hole from there, the number of holes is equal to the number of the Level. In this format, the only way to create an impossible level, is if the holes isolate a floor (making it impossible for the player to step on it), then if that happens, I also create a hole in place of the isolated floor, so in a simple way all levels that are generated are possible to win.
In fact I chose to make the game impossible to play infinitely, just to require the player's ability to reach higher levels, and as the game does not have much content, going infinitely would be kind of boring.
I don't have much intention of continuing to develop this game after the jam, but if I change my mind I will add more content and mechanics yes.
Again, thanks so much for the feedback!