first of all, this mod is very cool
second, haven't you thought about combining this with a nice first 4 levels mod "More Spelunky"? It's mostly focused on the alternate rooms of first episode.
third, the bugs:
1) the plague potion is much faster on the damsel (and other creatures) then on spelunker
2) if you open a chest with potion while holding it and standing in the end of corridor, the potion gets stuck in the wall. You can take it from there sometimes, but still it's ugly.
3) the potion breaks from falling but not breaks when bomb explodes or when a boulder runs over it. That's unexpected.
4) is there a way to empty the bottle without applying it on someone?
5) if you drink multiple fall-proof potions, there are multiple fall-proof animations over spelunker, but at the next level there is only one
6) the potions and mushrooms doesnt show themselves in between levels stage, while other objects show.
7) Effects sprites are not really good. I'll try to draw new ones later.

Is there a potion that cures disease?
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