Absolutely fantastic, cute, short, clever puzzler. It's awesome to have a single large holistic puzzle with a whole bunch of thought into making it all work together, something that's difficult in a game jam setting and why everyone else probably opts to make a set of levels rather than one complex one.
What I love is how each character has an intuitive set of properties and they all play very different from each other -- making four characters feel all unique and useful is not something even commercial games do well. As a result, you get something reminiscent of Thomas Was Alone's teamwork based puzzle platforming, but better. Only the penguin can swim, but its jump height is the smallest, so it needs help from another buddy for all but the smallest of jumps. Meanwhile the monkey can get almost anywhere alone, but its small size means it's not useful as a platform for helping others escape.
I did think I was softlocked at one point before I realized the penguin could make the one block high jump over the ice island on his own -- previously I had used the monkey to help.
One of the three perfect scores I've given in this jam (of idk, 50-100 I've played).