cpython VS upbge

Blender for Nim at https://github.com/juancarlospaco/cpython and maybe you can create it as a plugin on top of Blender ?, Blender has GPU, OpenGL, OpenCL, PBR, GI, SSAO, etc etc.

Over https://github.com/juancarlospaco/cpython we got bindings for https://upbge.org but I dont have time to make game demos.

What if I have a python object that contains Nim-managed pointers to nim objects that contain Python objects created by Nim's CPython ? How will GC(s) work ?

Starting with 2d games is very good advice however if the child is mostly interested in 3d, well not the most helpful advice.

Some people here forget that children are way more tolerant of not understanding things than adults are. They just want to get a quick taste not necessary dedicate their life to the study of game development.

I think something like RPG in a Box https://rpginabox.com/ is nice if the child likes Minecraft-style graphics. Also it is worth checking out if modding an existing games is something that might be of interest. Also blender is perfect, as it allows to focus on certain aspects on modeling first and in has an amazing game engine that can be solely driven by logic bricks: https://upbge.org/#/

Still, I think even something like Unreal should not be ruled out if the child is dead set on making a "real" game (9 years is a bit pushing it admittedly with help it might work out). For a visually-motivated child that has access to beefy computer, Unreal is the perfect tool to get things done early and fast. Load the starter template and they have a character they can walk around with in the first minute. Grab some free-for-the-month asset packs and they can make decent looking levels in a day or two that they can show friends and be proud of. And if they get to the point of needing logic, the visual scripting language is more than enough to make complete games in it.

Unreal is a monster of complexity but but perfect for just hacking together a quick asset-flip demo one can feel good about. They will learn about the realities of game dev soon enough, let them have some fun.

Also, if the child is the kind to need a more focused approach, blender is a nice choice

It's not as monolithic as you'd think. There are lots of engines out there but their communities aren't very vocal compared to Unity, Unreal, and especially Godot's community.

Take a look at: https://itch.io/game-development/engines/most-projects

And

https://www.gamedeveloper.com/blogs/the-generous-space-of-al...

If you look at both of these you'll see just how many engines there are and neither of these cover everything. There are plenty of engines popular in the Python community that no one outside of it are aware of. Such as Arcade [0], Python-Tcod [1], Ursina [2], UPBGE [3], and Panda3D [4]. But based on your description you'd really like https://gdevelop.io/. It embraces exactly what you're describing where you can build a game but just installing entire features others have made and put online into your game.

[0] Beginner friendly 2D library:

[1] Rougelike: https://python-tcod.readthedocs.io/en/latest/

[2] Beginner friendly 3D engine (built on Panda3D): https://www.ursinaengine.org/

[3] Blender Game Engine Fork: https://upbge.org/

[4] Highly flexible code first 3D engine: https://panda3d.org/

UPBGE which was formerly part of Blender is the only modern 3D engine I know of that supports Python for game development.

Otherwise, if it doesn't work, I'd suggest creating an issue at the UPBGE repository: https://github.com/upbge/upbge/issues

Yeah, they some people came back and revived it, they're adding some hella cool features like being able to render with eeve https://github.com/UPBGE/upbge

Link to issue:https://github.com/UPBGE/upbge/issues/1760

Another would be https://upbge.org/ 3D game engine forked from the old Blender Game Engine and deployed with Blender itself.