I hesitate to call "Creatures" a game. It is more akin to a toy or the world's most demanding goldfish. The furry creatures who roam on the screen have enough intelligence to disobey your commands, but not enough to obey them. You are given enough tools to spend hours in teaching and communicating with them, yet they never achieve the independence these tools are supposed to grant them. The more successful you are in keeping your creatures alive and breeding, the more difficult and time consuming it is to keep them this way. The downward spiral to total extinction become steeper with every newly born, as it becomes another burden rather then a hurdle.
Creatures fails where it matters most. Despite having no direct way to control and command the creatures, they require just these to function. Trying to prevent them from dying or straying to far to survive or even just keeping them healthy enough to foster the next generation, is a frustrating experience that rarely bears fruit. The indirect means of communication and tutoring are just not enough, or perhaps it is the creatures who lack the AI to benefit from your instructions for more then the immediate situation. It's not fun or even viable as a game, but even as a simulation it misses the point.
No matter how educated or capable your creature grows up to be, he still ends up requiring your constant attention. A task that can become as dull as it is frustrating when your creature decides to stay at a certain spot for hours, only to die mysteriously the moment you take your eyes off the screen.
There's potential there, yes. There is vision and sophistication that is sadly lacking in most Computer Games. But all of these are squandered on poor execution that will keep you interested for a good half and hour before being moved to the virtual attic to spend the rest of eternity gathering dust.