Alot of questions in there.

The target audience is pretty wide, there is alot of interest in these new "breeding" type games. The average age is usually 15, but you get a handful younger players, and a surprisingly large amount of adults. You also see alot of mother/daughters playing the game.
No, no other benefits except a first look at the game, the only advertising I did was to post on two other similar games announcing that we were going into alpha, so no paid advertising. If you want a bit of a sneak peak, I know there is a fansite that was created by one of the alpha testers, lemme find the link. Okay. tygras.silverkinz.com. Not too much on there yet, but it might give you an idea. xD
Yes, the site is VERY heavily graphics oriented, which is a huge pain. I'm a mega perfectionist with art, and finding the right artists has been a bit of a task not to mention expensive. But I'm really happy with the game's outcome, and I think it was worth it. I'm a big believer in working on the aesthetics of a game, although obviously you need to have fun game-play and solid programming as well.
Tygras will eventually be completely free to play, with the only pay features being upgraded accounts and "custom" Tygras. Custom Tygras are when you are able to design every aspect of your tygra from scratch, without having to breed for the look you want.
Anyhow, I'm also excited to see what the judges have to say. I'm hoping even if I'm not selected, they'll still give some constructive criticism.