Thanks for the comment!
If the 'Inspector' "sees" any slime or banana-peals you will get minus-points. By using clever positioning and by cleaning up the slime after oneself, it is possible to avoid getting any minus-points at all, but it requires training.
There are only minus-points in the game, so getting a negative score is the default.
This is my first real game-jam, so the UX might be a bit wonky 🙃 but thanks for the feedback! It is true that it might feel like you are failing if you get a negative score, I'll have it in mind for the future ^^