Reminds me of this small indie game called "INK". The mechanics are similar but it includes enemies that burst into ink and an ink splatter ability. It makes me wonder how this one would differentiate with the same core mechanic.
The platforming itself handles well and the ink mechanic works, but may be a bit small. The level design is a bit iffy since I found myself just jumping over everything until I reached the end of the screen/level/the camera wouldn't move anymore.
Great job, I do wonder if and how you'll end up expanding it!