I designed a game engine for a few games, implemented it on Windows 3.1, and assisted with its DOS implementation. The code running on this engine built equally

I designed a game engine for a few games, implemented it on Windows 3.1, and assisted with its DOS implementation. The code running on this engine built equally conveniently for Windows or for DOS due to the design of the engine. The publisher wanted the games to launch and run decently if "mem/c" indicated 500K. This was what was typically available in a 1Meg machine if it had things like Netware installed. We achieved this in part with commercial source-licensed libraries and in part with Borland's VROOM overlay technology.