The map has mostly "bouncy" weapons, such as the Ripper, the Rocket Launcher and the Flak Cannon. Take advantage of that in the sewer pipes, by shooting Ripper blades, Flak shells and Rocket grenades. The Rocket Launcher is on the higher part of the small pipe.
The Jumpboots are very useful in this map. You can use them to jump from the tanks 2 and 4 of the small pipe to the outside of the big tube in order to gain access to the BioRifle and the Damage Amplifier.
This Level is about one thing: predicting what your opponent will do next. There are mostly bouncing weapons in this Level to add to the strategy and the fun. These spots are good for shooting the Ripper Primary Fire or the Flak Cannon Primary Fire. If you see someone walking that way just stay a bit before the corner and shoot with your bouncing weapons. You're protected and most likely you'll kill the guy.
The Rocket Laucher Secondary Fire, the grenades are great bouncing projectiles but because of their relatively low speed they won't be very useful if you're in the lower part of the tube, the grenades won't have enough speed to reach your opponents. But you can use them from the top part of the tube, that's why I placed the Rocket Launcher there.
Now, when you're in the higher big tube, you have the possibilty to jump in the smaller tube that leads to the Rocket Launcher. If you jump to the side, you won't fall into that smaller tube but you'll walk on it and you can access a lot of goodies there, like the Armor...
If you jump from there to the ledges you'll see a lot of Health. This is a good spot because you're high so you're harder to touch, and you have the Health. The downside is that you'll have a jump quite a few times so that can make you vulnerable for a few moments.
Once you got the health there is also the ShieldBelt and some BladeHopper Ammo for your Ripper. So with the Armor, the Health and the ShieldBelt you should be ready to kick some serious butts now.
Now let's try something interesting. If you get the Jumpboots, you can get a lot of interesting pickups: Go [into] tank 2, above the Rocket Launcher and make your big Jump. You got the U Damage, only a few people know how to get it so it's there often. And now you can fall on your left on the pipe, and you have the ShieldBelt there. Another thing you can do with the boots is the same Jump but in the Tank 4 instead of Tank 2 . Now you have the Biorifle, with a buttload of Ammo. I know most people don't like this gun but it can really help in this Level, especially if it's crowded, you can shoot the goo in the foggy pipe with the Ripper or the Rocket Launcher pipe, or you can camp on the ledges with the health and use your Biorifle.
Although the map says that it can support 6 player matches, Inoxx himself recommends no more than 4 players in matches on this map.
We needed more One-on-One Levels so I did this very small and tight Level. I was a bit afraid of the beveled tubes, usually these slopes create bad collision problems in Internet play (with Unreal) but it worked well with Unreal Tournament. The Level was extremely fast with 80 polygons in view in the worst case. So I added fog. We didn't use fog until then for big areas because we wanted to keep Ultra High Framerate for the game. It's cool to have this great looking fog like in Unreal (ExtremeDark ), but usually it slows the game down a bit too much for smooth deathmatch. However, Fetid Sewers was so simple that the fog wasn't a big hit. I think the Level plays pretty well for 1-on-1 or deathmatch with up to 4 players. With more players it's becoming overcrowded and unplayable (like all the very small maps). The music was chosen for its "Underground" feeling.