I'm not exactly sure. I have a Blackjack II, but I've never really tried to download any of those games. In fact, my issue is not being able to delete the darn thing.
My best advice is that you try to download the game on your personal computer and then get the game onto your phone through ActiveSync. I'm sure that you can easily find Midnight Pool for the Blackjack II on any website such as cingular.com or something. You will have to pay for it though, hope that's not a problem for you. See how that works for you.