Return to Castle Wolfenstein
"Return to Castle Wolfenstein" received favorable reviews from critics. At Metacritic, it scores 88/100 (based on 32 reviews), and on GameRankings it scores 86.75% (based on 50 reviews). "Eurogamer"'s Tom Bramwell called "Return to Castle Wolfenstein" "a worthy addition to the stable of id Software affiliated shoot 'em ups. The single player game is average to good and takes quite a while to finish, but the game really earns its salt by shipping with a first class multiplayer element."
ShadowCaster
The "ShadowCaster" game engine, a successor of the "Wolfenstein 3D" engine and a predecessor of the "Doom" engine, was written by id Software's John Carmack and licensed to Raven Software. Carmack wrote the "ShadowCaster" 3D engine during his technology research after id Software completed "Wolfenstein 3D". The engine features diminished lighting, texture-mapped floors and ceilings, walls with variable heights and sloped floors. The engine was "about half as fast as that of "Wolfenstein"" but fit the exploration of "ShadowCaster" rather than the fast-paced action of "Doom".