How long does this game take?

About 30 minutes for one regular game.

Crystal games 60-90.

Crystal games with Choosen ones can (in theory) last more then 24 hours. Realistically is 45-180 max.

Wow, thats a long game.

What do you mean by long? The 24 hours? That one is highly theoretical. I would need 2 players with the biggest and slowest decks possible, both of them recycling their decks (and the opponents) as often as possible (and at the last possible moment). All the while neither may get a big advantage in the game, so all of them end in a draw (and thus 1 crystal). Finally, each player must win 4 games, so it comes down to the 9th game in order to get the 5th crystal. If you menage to pull that one off in real life you deserve it ;-)

That said my longest (league) game was close to 3 hours, split into 3 very balanced games.