I'm not getting any issues on my end. What settings are you using exactly?
---------- Post added at 01:53 PM ---------- Previous post was at 01:47 PM ----------
Actually on closer inspection I might be able to add something to the thread.
I typically run SRB2 in windowed mode; there I experience no problems with OpenGL.
If I use fullscreen, certain portions of the screen will become black depending on the resolution. In normal resolutions, just a small top sliver of the screen is black, whereas certain higher resolutions will cause massive amounts of the right and top of the screen to be cut off.