If you have ideas let me know

Basically, for the game to work well you would have to create games that don't rely on timing, so most board games would work, even turn-based strategy games. Writing that right now the first thing that comes into my mind is "Battleship". Maybe you could either play against an AI if the cable is not attached and against another player if it is. That would be pretty cool. (I might work on that if/when I finish my current project… )

I think one of the best things you could do for a game utilizing two calculators is to make games where player 1 shouldn't see player 2's screen, and vice versa, or games where you need more controls than one calculator can provide.

I think multiplayer games would be best made with this, as most people don't have 2 calculators to put side-by-side, meaning making something needing 2 calculators to do one thing would be only available to certain people. However, you could use 2 calculators to speed up calculations for games, such as:

Calc 1 constantly updates display and Calc 2 constantly is running calculations that Calc 1 uses to update display.

_{And I'm kinda back from my long leave, but I have been monitoring some of what's going on. Also, someone accidentally cleared my ram before I saved some stuff, so I lost a lot of my programs. However, that gives me the chance to redo everything more efficient. And one of my friends might get into calculator programming so I need to get back on top of things.}