I had two thoughts on this Ask (I don't have children, but I do have two nieces and constantly work to inspire them to creativity in the arts and sciences. I do care).
If your son is copying something else he's seen someone do, or if he's really into games and his friends also share this interest [1], then you can't beat the 2D approach. If you can find the right software, then you help him learn the software and he goes to town. He will need to adjust his ambition to what he can accomplish with the software. He already knows what he likes, and you're there to help him participate and get out of the way. ahaha
My other idea is there is an educational angle to "games" as a collection of skills and knowledge: problem solving skill of breaking a goal into parts. All games are in some form about probability, and *probability modeling* animations can be really cool. (I saw this post on reddit today [2]). Modeling is a great skill or tool in your toolbox. You can go really fast with this approach, and get to an abstract but interesting outcome. Maybe something that involves using a keyboard or mouse for interactivity and probability. If he loses interest, then maybe it wasn't going to last anyway, but you planted these educational seeds which can grow later.
[1]: I remember when I was his age, and I had five friends who lived six blocks from my house next to a park. We would get together to play touch football. I remember going over to this one kid's house trying to get him to come out and play football in the park, and he was showing us this 'computer' thing he had, Commodore64. I remember not having any of it, and we left. haha. That was _not_ my introduction to computers.
[2]: https://www.reddit.com/r/oddlysatisfying/comments/19bgdvr/th...