I Made Minecraft, but It's 4D [video] (youtube.com)

very nerdy concept! And well crafted video. But as a gameplay mechanic not my cup of tea.

I was really impressed just by the fact that this is fully functional. It's a funny headline but getting all the technicalities working with pathfinding, collisions, rendering etc. sounds like a nightmare. Coincidentally, spiders crawling through the 4th dimension to attack you from a plane you didn't even see is also that. His other video on making a 1D game is a similarly fun concept but I believe it was more of a game design challenge than a technical one. Cheers, great video.