interesting that you mention alchemists, bec that game felt very samey to me after about 5 plays, and i can't enjoy it anymore.
however, petz i have played about 20 - 30 times, and it has felt like a new puzzle every time.
meanwhile, nations the dice game, which is much more random than petz, started to feel samey after about 10 - 15 games, and food chain magnate, which is even less random than petz, started to feel samey to me after only a few plays (not trying to disparage these other games, samey-ness is a feeling, and perhaps each person feels it differently).
however, petz i have played about 20 - 30 times, and it has felt like a new puzzle every time.
meanwhile, nations the dice game, which is much more random than petz, started to feel samey after about 10 - 15 games, and food chain magnate, which is even less random than petz, started to feel samey to me after only a few plays (not trying to disparage these other games, samey-ness is a feeling, and perhaps each person feels it differently).