Flash runs bad on slow pcs maximized
If you are creating an app or a game, never listen to the people complaining about running bad/slow on old PC's. You design the game how you want, specify recommend hardware specs and even minimum specs. The people with hardware lower than minimum specs can either not play the game or upgrade their slow POS... Sure you want as many people possible to play and enjoy your game, but at what expense?
I don't see people telling Blizzard that the newly released Starcraft II will not run on their 686 with an integrated video chip.
That's one thing about this hobby that really gets me... People will spend hundred's on building their cabinet, nice controls, nice artwork, but they will toss in an old ass PC to run it. This is like tossing a Ford Festiva engine into a nice new Corvette body. Sure it'll run, but don't ---smurfette--- when you can't beat a minivan off the light.
To answer your question, it's possible and it's been done before as stated above.