There are plenty of games that adapt to your actions and you end up with very different storylines and endings. The character chooses but the code is unaltered. The code was set in stone but the way the model is programmed to behave changes depending on actions. I imagine the actual reality is more like the simulated universe you were placed into with very real boundaries of what’s possible, but the dynamic nature of your characters actions amounts to infinite possibilities since it’s not hard coded. One could live the life of an NPC, or they could do something more adventurous.