IMO it should *scrape by* with lowest EVERYTHING using a mid-2000s laptop. Quick idea: multiple versions of the game for different computer specs? I'll use NFS graphics as an example, since there are SO MANY NFS GAMES.
-One release for wimpy-ass computers (i.e. voxel graphics and/or NFS1 graphics)
-One release for low-end computers (i.e. NFS Hot Pursuit 2 graphics)
-One release for mid-range computers (i.e. NFS Carbon? NFS Undercover?)
-One release for high-end computers (i.e. NFS ProStreet or NFS The Run)
-One release for SUPERCOMPUTERS. (i.e. the latest NFS Hot Pursuit or better)
Put simply, the models, textures, and default effects would be changed for each release, but the physics, gameplay, etc would stay exactly the same.