Smooth Doom MBF21 (or SD21 for short) is a recreation of the original ZDoom-based Smooth Doom using MBF21 and DSDHacked, therefore making it playable on a handful of ports outside of the ZDoom family.   SD21 comes in two flavors: the standard edition features not only smooth animations, but also some of the original's optional fanciness features, such as extended gore, extra particle effects, bullet and shell casings, extra decorations and alternative death animations. If you want none