Well, it's always the same things : -Why didn't you include the fisheye lens? (Sega themselves couldn't do it but people still expect you to pull a miracle) -Why don't you use sprites instead? (seriously??) -The game should focus on exploration instead of reaching an end goal. -The game should focus on speed instead. -Why don't you make Sonic Utopia on Saturn instead? (never heard of RAM? Limited draw distance?) -Why don't you port Sonic Mania instead? -Where are the bosses? etc. So it's super annoying to push an update just to receive 100 comments of people already nitpicking, asking for something else, complaining, asking for more, etc, so I'd rather move away from this project as it's not even fun anymore to do it, it feels like I'm working. Anyway, about the BSP tree, I'm pretty sure that's what the Slavedriver did, as you can see the maps have all sorts of weird small polygons/triangles all over the place, which shows that it was automatically processed, so the most likely answer is a BSP tree. So I'm not sure right now between 2 options : -manually placing portals, keep an octree and just use a pvs for occlusion culling (more work, more overdraw, but way faster for the CPU and less quad subdivision). -Using a full-BSP compiler, so everything is automated, minimum overdraw but slower cpu operations and more quad subdivision (more vertices, more draw commands, etc.). Considering my own experience with Saturn Quake maps, using 64x64 textures is really pushing the Saturn hard, while 32x32 makes it much easier. The Slavedriver engine used 64x64 only with gouraud shading everywhere, which shows how good it is, but I think its bottleneck is the CPU since it also slows down in emulators, which never happens to me within emulators when I use high quality textures with gouraud shading, while CPU issues do slow down emulators. So with 32x32 textures, overdraw isn't as bad.