There are few fantasy RPGs that have a really interesting way of playing an alchemist. Most of them require a tremendous amount of forethought and bean-counting as you buy and construct your alchemical creations ahead of time. D&D is among the most egregious of these.
I like the idea of playing an alchemist, but that's not the way I want to play it.
Here's the sort of alchemist I want to play: