I might be a bit dumb, but is there a way to unpause without loading to the start of the level? I found myself pausing to take care of other stuff irl many times and then having to load back to the start of the level - for some that are many screens long this is a major annoyance.
No, it is intentionally not allowed to pause and resume, to prevent “pausebuffering” exploits.
However, if you are in a “safe” place and not just pausebuffering, you should be able to alt-tab out of the game which will also pause everything (but if you do that within a tight platforming section, you’ll likely be unable to press buttons in time and fall down).
The pause buffering makes sense, esp given that the platforming is surprisingly hard due to how slippery movement is. Alt-tabbing is a good workaround, but it feels inelegant. Perhaps just disabling movement for like a half second after unpausing could work, but then again I'm not a game developer so I'm not sure what the best solution to the pause buffering problem is.