Is this a mental excercise, or not?

I found this Flash game online called "The Codex of Alchemical Engineering"

http://www.kongregate.com/games/krispykrem/the-cod...

A surprisingly intellectual game: a rather rare find in the pool of common, simple and addictive flash games. My question is this: In the later levels of this game (Elixir of Life, Philosopher's Stone, etc.) where complex molecules are formed, is this a true excercise of the mind any longer? Or is this higher complexity merely a disguise for repetition and quantity, as opposed to quality and novelty?

In general really, when does some intellectual task, such as studying an Academic field, learning a new practice, or studying any type of complex sustem, stop being an excercise in critical thinking and instead becomes just a test of memorization and computation?

Obviously this question has no concrete answer. I'd like to hear the thoughts of the Y!A community on this dilemma - anyone with knowledge on the psychology or neurology of this please step forward.

P.S. For the Flash game addicts, (I confess I am one of them), there's a more challenging version of this game here: http://www.kongregate.com/games/krispykrem/the-cod...

I haven't dared to attempt any of these yet - I still need to beat the last level int the first one.