The one-shot game is definitely the hardest one here by a long shot, no idea why this is considered easier than having a model on pager duty. Aside from needing to generate coherent assets and having a meaningful creative vision, a good game is hard to make because it requires a lot of taste, not being good at programming (see the many indie hits from people who learned to program just to make their game, and were wildly successful with atrocious code).