[andypants]

But games are all different. An improvement to the engine for one kind of game may not be an improvement for another kind of game. Most games would probably only use a small part of the engine.

Will the engine become a monolith with support for pretty much everything, and all games using the engine will only need 10% of it? Or something else?

I think you need to state very clearly what the goal of the engine is (best 2d engine, best tile game engine, best ??? engine, general purpose engine, etc?), which can help define exactly what kinds of contributions are actually useful.

[coldtea]

>But games are all different. An improvement to the engine for one kind of game may not be an improvement for another kind of game. Most games would probably only use a small part of the engine.

I don't really see them as all different. Especially at the engine level. Especially considering most 2D engines (Cocos, Game Closure, etc) are mostly the same and use similar concepts.