First of all, there are many things I liked, which are:
the overall idea of restoring color as you collect potions
the ai, which is simple but doesn't look trivial
the map is quite varied and fun to explore
the fact that living beings only drop potions that you are missing (very neat).
But still, I played your game to the end because I felt like it needed a wise rating. If I was playing it for fun, I would have stopped. I think this is because your game has short-term goals (killing enemies, chopping trees etc.) and long term goals (collecting all potions). The first ones can get repetitive quickly, while the latter can feel distant and not engaging. So I think you should add some mid-term goals, something like getting to a destination for any reason (and collecting potions in the meantime) or collecting a small amount of potions to get a reward like a more powerful sword.
Something like this would give more meaning to the short-term goals and make the long-term one feel less daunting and more like "I will get there while doing these other tasks".
So I think it has a great potential and you should definetely work more on it, it could be really good.
I see in other comments that it was deeper than it looked to me, like you could avoid killing humans and chopping trees to have a better karma. You should make it clearer, because it's an interesting concept and it's a shame that it can easily pass by and be ignored