Only mildly fun.
I will give you compliments for going out of the ordinary in terms of how to go about doing the whole "evolution" concept. Good job on being different!
I think you need to work on the graphical interface of the game - it wasn't aesthetically pleasing.
You could also work on some sort intro - it all seems too random for the betting to really count (either that or it takes A LOT of trials and no-bet-races).
Could use some better audio too.

Other than that, good job on the originality and concept.

i like it its fun the only thing i dont really like is that the story continues to change

was kinda confuzed when playing... but i guess the game was alright...

Graffics are crappy but it was fun to play., i actually played it alot longer then i thought i would. good job just needs more flash and some refinement i think