I think $14.99 would be a good initial Steam Early Access release price...
$19.99 or $24.99 for the final release.
Imagine a kid who doesn't have a lot of money, maybe $30...
In all his excitement, he asks his mother "MOM, CAN I GET THIS GAME? IT'S SO COOL!!!"
She says yes, buys it for him, he gives her the money ($14.99), and starts downloading the game. When it's done downloading and after it's installed, he tries to play it, but it lags! It lags so much, he can't play it at all, even on the lowest settings. So, the kid says "At least it wasn't $30! I still have $14.99 left, so I'm gonna go get BattleBlock Theatre on Steam, because I know I'll be able to play that!" If it were $30, he wouldn't be able to get any other game. You screwed him over big time (Even though he should have read the System Requirements), because of a game that's fairly overpriced. I think $20 is a great price for KF1 and 2 (Separate, of course). If you want to make money, create a bundle at $50 that includes KF1&2 with most DLC. Of course, all of this is just in my opinion, but I don't really want to pay $30 or more on a game that may not be completely compatible with an nVidia GT 610.