Thank you for feedback!
Will think about the hints, maybe it is not too clear on what to do, but my idea was, the player kills enemies and gets an antidote, that could be used on other defeated animals (icons that remains for some time after killing an animal) to "cure" them, and for each level there is particular amount of targets that have to be cured (panel at top right corner).
Have not though about removing explicit cure from the player until this moment, but the story depends on it, hmmm.
And i guess the better idea is to make auto "cure" if the player have more than particular amount, so it could steel exist in the game lore and advance level completion.