Since this thread will contain the intersection of people interested in coding games and people interested in AI, can I ask whether the latest AI coding tools can help someone vibe code a simple low-poly 3D game? I only ever used Twine before.

Yep. Simplest is browser game with three.js, the only lib you need. But for low-poly 3D, you can basically tell the frontier LLMs to build yourself the rasteriser itself in whatever language you want (not recommending it, just saying they're that good). Literally just put your comment into Claude Code or Codex and see it do it.