E4M1RMX was part of the Remix Quake Mapping Challege, which was run over on a Func MsgBoard thread (see link above). I opted to do Quake 1's E4M1 "The Sewage System", mainly because I was the most comfortable with the 'base map' theme (seeing as most of my previous maps had been in the 'base' style).
My version used Speedy's Speedbaze texture wad, alongside a few of the original Quake textures. I incorporated some subtly coloured lighting into a small layout which doesn't really deviate very much from the original map's plan. To make things interesting I changed all of the original map's water into corrosive slime. The map had a lot of water sections (being a sewage system it is full of pipes and underwater passages) so this is an important factor in the map's gameplay. EV suits (used to protect the player from slime) are spawned continually in suit-dispensing machines, which are dotted in positions around the map.
The map sports plenty of secrets, including powerups, weapons and health/armour stashes. The Quad-damage makes an appearance twice in this map, and this makes for some good 100% speed-run possibilities. I have made a demonstrative demo and posted it [here]!
This map was added to the Speed Demos Archive, and there are several much better runs than my rubbish one!