I know everyone has super rose tinted glasses when it comes to OS/2, but try it on period hardware, with what shipped in 1987. Its terrible. And yes it runs great on Pentiums or anything new under emulation as clearly the larger fault is 1987 hardware, namely the 386.
I was using it on period H/W, and in at least one case it was an IBM PS/2 with an 8514 graphics adapter and writing to it using some graphics primitives. The only wonk thing I recall was that if I cranked up the compiler optimizations, it just drew lines at various angles all over the screen instead of the images I needed. IIRC there were a few cranky things about writing directly to the graphics but I don't recall problems otherwise.