This does sound like a perfect fit for the Game Creation domain in SDGP.
If not SDGP, Iโd happily construct this as an RFP SIP that requests a collection of proposals. In the proposal we lists a few examples of their work that we can rank order in the voting
Maybe I would make it a $30K SIP and the top 3 winners would win $10K work a piece?
Probably would be super easy to do.