Pixelrebirth and I were discussing this in chat the other day, and I thought I'd mention it on here, see what others thought of it.
A long time ago, before some of you were even born. A guy called Peter Molyneux, had a great idea for his games. He came up with this idea that each game would in some way be linked to another. Even though the games would be entirely different. For example, a game like Magic Carpet (Bullfrog) would put you into another game based in the water if you flew into the ocean, or if you flew really high, you'd be in a Populous style game. But only if you had those other games installed, otherwise it would continue as normal. Each game would still be it's own game and entirely playable on its own. But doing certain things would let you move over into another game. Events in each one may or may not effect things in the other games,
Nothing, to my knowledge ever really came of that, probably because Magic Carpet wasn't really successful, though technically was really good for its time. But it did get me to thinking it could be pretty interesting if it were done here, with construct games.
A lesser and simpler method would be unlocking game content from one game, that applies to another game. For example you could find a special object in a Zelda style game, that has a curious combination written on it. Which turns out can be used to unlock a bonus level in another game. While simply completing another game, will unlock a special edition weapon in someone else's platform game. So on and so forth. Different games entirely, but grouped together by the bonus content (not game breaking content, or content required to complete the game. Just bonus items, levels, features etc.).
It could also help to get the not so visible games noticed more than they might have been otherwise.