My first play through I could hardly craft anything because I got overwhelmed by the enemies. Second play through was a little better since there weren't as many enemies on screen (not sure what mechanic effects this, maybe the number of ingredients you own?).
For a frantic game like this it would be helpful if I had 3/0/0 and wanted to increment to 2/1/0 without needing to allocate manually would have been nice. As in if only one ingredient has points, if I go to another one it will automatically decrement the other ingredient if I add points to the other one.
Just a suggestion since allowing the player to craft faster would give them a better advantage since it does not get easy dealing with the hordes berating you. Well maybe if you craft certain potions (I like the yellow potion since it can give me a breather). Its a fun concept all around though!