Ever try typing those into Heretic?

Was Sega not very big in the US in that era? Most of the old gaming references I see online are NES-based (or at least Nintendo), but the first cheat code I learned was Up, Down, Left, Right, A+Start.

Up, C, Down, C, Left, C, Right, C, A+Start was cooler.

Sega was pretty much unknown in the US until the Genesis came out, and never really beat Nintendo in popularity.