A cool idea, but not very well executed
First off, it's a fairly original concept, and it's fairly simple. All you have to do is move your creatures around and choose when - and what - to evolve. The tree of life system allows you to decide what to evolve for a maximum score very easily. The scoring system is also good, with the person who gets intelligent life usually - but not always - winning. The background graphics are adequate, and the animations for the animals are nicely done. Music is just right - atmospheric with a nice "jungle" sound, but so subtle that you hardly notice it's there until it goes. The game also has an individual sound for each creature which all sound like animals.
My first criticism is that I didn't get the poster and book that were supposed to come with the game, although that may be that it was distributed by a different company. But about the game itself.
To begin with it's clumsy. You have to use menus and windows all the time, when it would have been much easier to have everything on buttons on a sidebar somewhere. Also the map doesn't scroll - you have to use arrow keys or right click to re-centre the map. You can open more windows at different parts of the map but a larger, scrolling map would make much more sense and I really don't see why Crossover did it this way.
Apart from this dodgy system of navigating the game, I also found that it became fairly easy to win. The designers have tried to make it easy for competition to the end, but in practice one player can evolve several species and block anyone else from getting anywhere, because only one person can own each species. Extinction re-opens that path but usually the same player can re-evolve that species more quickly than any other player can.
Also the battle system leaves a lot to be desired. It really seems pointless as you can easily win the game without it and the computer players very rarely use it. Usually the best fighters are those who don't evolve to anything useful so they're really a waste of time.
And finally - it's dull. Time is spent hanging around waiting until your species evolve, then deciding what to evolve next and waiting some more. There is very little replay value as each game is very like the next and can always be won with the same strategy.
The Bottom Line
A unique strategy game which tries its best to make the Earth's history into a competitive simulation. Unfortunately, bad navigation and a far too basic gameplay design mean that this game is not interesting enough to keep anyone's attention.