its like a single dev working in UNITY and if you spent more than 5 seconds on Unity you know how annoying it can get lol, its a WIP so it wont be finished that fast also I think this is his first game.
think twice before assuming someone doesn't use unity. i know how it works and I'm a user of the program myself working avatar edits and commissions myself along with substance painter and blender. so i know what it takes to work any of those systems thank you.