Sorry to reply to an ass-old thread, like actually two decades old, but I have every reason to answer. Every single one of my lucid dreams take place inside of a video game, without fail. I will make a thread asking about what game engine your lucid dreams are powered by. My lucid dreams used to used to be powered by a modified version of the Hedgehog Engine from Sonic Generations, and would use assets mostly from Sonic Unleashed. These older dreams also all featured a gameplay style mostly similar to the 3D boost Sonic gameplay, more specifically adapted from the Wii version of Sonic Unleashed, where you can't hold down the boost button, but instead release the boost in short bursts, but otherwise with controls from Sonic Generations.

I would technically play as myself, as my dreams take place in the Sonic the Hedgehog universe, but a few years after the games would canonically conclude, and because of that, Sonic is dead, and Shadow has gone missing. Other Sonic characters, such as certain NPCs from Sonic Unleashed, and especially Dr. Eggman, do still appear and are sometimes relevant to whatever small plot a particular dream has.

Later on, my dreams switched from using modified code from Sonic Generations to using Valve's Source engine. Because the Source engine wasn't really designed for the gameplay of my dreams, more bugs were introduced. I think the Source engine was used solely because it was a more optimized engine. My dreams always targeted 60 FPS, but prior to using the Source engine, they had a lot of trouble actually running above 40 FPS. Still better than my waking life though. Now with the Source engine, they run at 60 FPS at least half the time. The gameplay is still the same as before, but now with additional bugs.

There are two outliers of dreams that, while still being based on the Source engine, have completely different gameplay. One is basically a level pack for Portal 2, but you play as Lori Loud from The Loud House, and features a ton of new commentary from Cave Johnson. The other is a rhythm game that plays exactly like the Persona Dancing games, but has different songs (most from Sonic, some from Persona, and a few from other sources), a completely different character roster mostly featuring Sonic characters, but not Sonic or Shadow, and a completely different plot (though Persona 3/5 Dancing in Moon/Starlight had no plot).