The graphics are really cute, and I like the dialogue between the mouse buddies. The music during the chase is also very fitting, and I like that in the beginning you can choose to reject or accept your friends' offer to help.
I see that a lot of other people have commented on the difficulty. As a general rule of thumb, for game jams, you should ideally make your game really, really easy to beat. The reason for this is that since there's a bunch of other games to play, if people get frustrated with yours, they're more likely to move on to another one. Additionally, you won't get feedback for the later parts of the game since they can't reach it.
There's a couple of things I would change. First, add coyote time, which is the grace period where you can still jump after leaving a platform. It was really easy to accidentally slip off a platform when I was trying to jump to another one. I also think the gravity should be lowered a little, and the hazards should be more clearly marked. I could see that the lightning was harmful, but the white puff clouds were not obvious at all and the rocks are really hard to see. Finally, I would decrease the speed of the tentacle monster, I think he catches up to you a bit too fast.
You've got a really comedic story and some great graphics with it to boot. Unfortunately I wasn't able to beat it, I would have really liked to see how the rest of the story plays out.