Yeah, that level - or rather its content - seems to be dysfunctional.
Level starts at 27fps for me (a joke, regarding the number of objects in that level), the fps count is raised by 1-3 fps per enemy killed or magic object collected. By repeatedly untoggling and re-toggling all the shaders in the F11 menu, I can get actually get 60fps for a while, but with psychedelic light effects in certain locations, and the framerate will drop to around 40 soon.
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