I'm experiencing some rendering issues: when standing onto or directly underneath a section of wall, the wall texture is twitching. I've put some screens with comments here. I've searched the bug tracker but I couldn't find any related unclosed issues. This only happens with the software renderer (prboom-plus.exe). This happens while using the default config, but it's more noticable on higher resolutions (linedefs seem to move more). My version is 18.104.22.168, PrBoom (regular) 2.5.0 has the same problem. My OS is Windows 7 32-bit.
Also, I've tried to Fraps it, but I couldn't find the "Use GL surface for software mode" option entryway was talking about. Selecting OpenGL as video mode doesn't work.