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.
Trivia
Although the map says that it can support 6 player matches, Inoxx himself recommends no more than 4 players in matches on this map.