It's possible for TGF 'cause I saw articles/engines on it, but I never really took the time to look at. But I did come up with a way, but because of the object limit in TGF it might be hard to do; "instead of moving the player in front of the background, make the whole background active objects and move them". But thats just theroetically speaking, i didn't try it yet. (never had a use for it)
I can think of a way, but it involves ini's and two windows....might eat resources a bit. ANYWAYS:
first you need to make a custom window for app1...and you need the "mouse" extension and the "window" extension (sorry i don't know the real names.)
basically use app1 as player ones screen and app2 as player twos screen.
always make app2 right where app1 is but underneath it, and use ini's to track the movement of each player for the other app. it would work, but might be a little strange. and also record if the windows open or closed so they both close at the same time.
hopefully you understand that
I'll make up an example if i have time, and post it on here later.
thinking is like pong, it's easy, but you miss sometimes.