I have seen many of people complaining about RAZE's 26th level. I still have yet to beat it myself, but I have gotten 1-3 kill left many of times. Below are hints that will help you if you can't get close to winning.
~Aim for the human, unless you see a robot with little health. ~Don't chase a robot with a Railgun. ~Try to get the 2x damage modifier at the top. ~Don't die because I notice that most of my team's deaths are from me. ~Keep the Railguns away from the enemy because they kill you in one shot. ~Keep your cursor near your player because you will get less lag. ~Pick up the health packs on the top corners in the elevators, even if you don't need them because the enemy will use them. ~Try to dodge grenades because these kill you in one shot 95% of the time. ~Try to combine the Grenade launcher or the Railgun with the 2x damage multiplayer. ~Try to back up teammates with low health if they are being shot at by an Uzi. ~Use your best weapon. Note: You also need to have good aim to.
If you have, any other hints feel free to add them to the list. I will add more if I find some. Last, add feedback about hints for level 26.