OpenTyrian SDL had been ported to OS/2-eCS (2014-07-25)
http://hobbes.nmsu.edu/h-search.php?key=OpenTyrian-SDL-
"OpenTyrian is an open-source port of the DOS game Tyrian. Tyrian is an arcade-style vertical scrolling shooter. Requires SDL-1.2.15 for OS/2."
Official Project URL: https://code.google.com/p/opentyrian/
Port by: Andrey Vasilkin