The reason it won't really work for gamedev or complex software is that the risk of the business isn't really in the product-market fit, but rather in stellar execution.
If your business idea is dependent on being able to do a complicated thing, then a POC or a demo might make more sense for testing the waters and seeing if there's any technical impediment to the idea
If your business idea is dependent on being able to do a complicated thing, then a POC or a demo might make more sense for testing the waters and seeing if there's any technical impediment to the idea