The shared D3D device part is actually the real magic here. Getting two render loops to cooperate on the same GPU context without stepping on each other is not trivial at all, especially with games that were never designed with that in mind. The fact that both worlds stay simulated simultaneously is pretty wild too, it's not just rendering one and pausing the other. GTA modders have been carrying the entire franchise's innovation on their backs for like a decade now lol.

The video mentioned: https://www.youtube.com/watch?v=X_w6fo4KVy0

Writing custom scripts in PAWN and then later mods, hacks and cheats for CLEO was my personal gateway into coding. Most RP servers were so nepotistic, so that was my way of getting back and fighting the "system". Fun times, do not miss it tho.

One of us, one of us, one of us

So, is that how we unlock HL3? Play HL1 in HL2..

GTA V already runs on the steam deck. Even the enhanced edition does https://www.youtube.com/watch?v=QtKjHSn9a5U

Your comment surprised me given GTA V can run on Intel HD 4000 at 40fps with tweaked settings https://www.youtube.com/watch?v=fo2qGdXnabk Which is not so surprising given GTA V is over a decade old at this point.

I've played through the whole of story mode with no more than a few rare world streaming issues and that was a couple years ago. You could give it another shot, I recommend binding the gyro to one of the back grip buttons for precise aim.

Better yet, get the original release of GTA: San Andreas. It holds up to several replays in a way that GTA V does not imo.