[Pxtl]

There was a clever game called Metal Marines back then that exploited this idea - the game was a 1v1 base-building RTS where each player's "base" was on its own map in its own window. When you fired missiles or launched APCs from one base into the other, the missile would fly out of your base window, over the desktop and into the other window to hit his base. The effect was jaw-dropping even though it was a simple and cartoony game.

[viraptor]

Thank you! I was looking for that game a few days ago, but couldn't remember the name at all! And it looks like there's a reboot of it on Steam: http://store.steampowered.com/app/335940/

[zyxley]

That game was amazing. I wish I'd gotten good enough at it to ever get past the first few levels.