Probably one of the main things I think the game is missing is any sort of gameplay mode where you can pick a specific set of items instead of rolling a random set. I would love to do entire challenge runs with a specific set of only three items, or a run with multiple of the same tool.

I also feel this way about levels: sometimes I see a level and want to replay specifically that level over and over with different combinations of tools, but with the way the game works, this is impossible.

If there were a mod where I could go into the Changes menu and create a custom run and hand-pick what happens, what level I play, or what items I get, that would probably make my year.