Interesting minimal platformer. The animation style makes me think of VVVVVV.
I know this was made in 48 hours as you describe, so some of my feedback might suggest out-of-scope ideas, but I included them all in case you decide to expand in the future:
I thought the intro scene was a bit long, but I wanted to jump into the action sooner! Maybe the story can be intervowen into the gameplay little by little. I like the tone and atmosphere though, quite engaging.
It wasn't very obvious at first that the goal is to head towards the door, as the dark rectangular shape wasn't immediately recognizable. Perhaps you can point it out with a little arrow (at least for the very first level). The first time I played it, I noticed "p-skip" in the corner, but didn't know it meant pressing "p" would skip the level, so I accidentally skipped some levels.
Controls wise, personally I prefer to use one hand for movement, and another hand for jumping (normally I expect to use the spacebar for jumping). In the end, I used WASD to move left/right, and the up arrow on my right hand to jump.
Cool mechanic with the "working together" bit. So the idea here is to make the ghost-shaped character stop on a space that has a dashed outline. It wasn't apparent at first that once you move over a tile, the space is filled in and you can no longer traverse it once you leave "working together" mode (hence restarting the puzzle becomes necessary). I felt the two mechanics were a bit disjointed—the platforming vs ice floor puzzle. A little bit of onboarding might help.
Overall, I am quite impressed. The game includes music, sound effects, narrative, transitions—not easy to do in 48 hours. Bravo!