Making your game general

ITT we discuss how to collaboratively design our games.

2D single player is much more doable for indie devs who are working alone. You really can't argue with that point, but you will anyway for some reason.

Tons of free 3D engines. Tons of Free 3d assets.
Tons of game templates and ready-made scripts.
You can make a MOBA, FPS, RPG with less content than first Diablo, and people will play as long as its immersive.
You can easily make the next Fortnite.