> Are their hands tied by legal

Yes.

Even if you're the owner of the game, the contracts for the voice actors, motion capture, models, etc. frequently define very narrow terms of usage. Defining the exact release platforms is common. Not to mention profit sharing if the actors or studios you're hiring are popular.

It's even worse for retro games. Many times the original rights holder went out of business, sold their rights, died, or something else that muddies the ownership chain.