I see that there's currently only an "any%" category for the game, with no difficulty settings or 100%. I also noticed that the comment on episode 1 said that the higher difficulties don't work, which isn't correct- they just have a slightly different requirement. Anyway, proposed categories (assuming for all 3 episodes but I can't personally say for episodes 2 or 3):
Easy: Requires collecting any 10 numbers to open the door. Medium/Hard: Requires collecting all 20 numbers to open the door. The difference here is in Gruzzle behavior- Hard has them respawn and be "smarter", as well as having less slime available. 100%: Requires collecting all post-level bonuses. This requires not having "Skip problems" selected and collecting the numbers from 0-9 twice, getting all trucks correct, getting all problems correct, collecting all collectibles, and accessing all secret areas. Damage can be taken. Due to the forced math problems, a "100% collection" category that meets all of the above requirements without the math problems would probably be a better category- less RNG from the mid-level problems, no interruptions.
In summary: Any% Easy, Any% Medium/Hard, All Collectibles, and 100% would be the ideal category list for this game.