I had a thought a while back. PopCap has a bunch of puzzle games where the premises are pretty similar, right? Match things that are the same color, through various means. Bejeweled, swap them, Zuma, shoot them, AstroPop, attract them, Dynomite!, bounce them, Atomica, slide them, etc.
What if we combined all of these games into a sort of crossover, PvP style game, a la Puyo Puyo Tetris?
Playable characters include:
Felis (Bejeweled)
Corvus (Bejeweled)
Hans (Zuma)
Steggy and Tank (Dynomite!)
Vector (AstroPop)
Atomicus (Atomica)
Probably a few others, as well?
Each game plays pretty much exactly the same as the others, with a few concessions made to encourage balance.
Bejeweled: Plays like the Avalanche quests from 3, with the added stipulation that gems also fall one at a time every few seconds, to keep the tension going.
Atomica: Plays like Action Mode.
Each game also has its own obstacles to receive when the player is attacked:
Bejeweled - Coal, bombs, locks and Doom Gems, depending on the strength of the attack. Bombs either tick down move by move or in real-time, with a different design for the real-time bombs to differentiate them.
Zuma - Black balls that don't match with any color but can be destroyed by making a match with a ball that touches them.
Dynomite! - Cracked eggs that don't match with any color, like the black balls in Zuma.
AstroPop - Stone walls, metal walls and plague blocks, depending on the strength of the attack.
Atomica - Biohazards. The timer on the biohazard depends on the strength of the attack.
In any case, the defeat conditions are the same as in their respective games.
I wish I could have also included Chuzzle and Alchemy, but I'm not sure how the mechanics of those two games lend themselves to not having a full board. (If anything, in Alchemy, having a full board would be a GOOD thing, if it were possible at all.) Ironic, considering that Chuzzle is one of the few PopCap games to canonically have a multiplayer mode.
There are probably others I'm missing, so please, I'd love to hear your feedback!