You said you are working on power-ups. How about power-ups that do things like increasing stompping power of your weapons, recieving less damage from enemy weapons, extending magizines, and increasing your agility (jumping and running).
I am also working on a design for a H.U.D. that would display health, ammo, score, and other information. It would be displayed on a new player-type the "Teir Player" and come with a Game-Mode, "Team Tactical Death Match" (TTDM). I will post a picture of the new H.U.D. on late Sunday or sometime Monday.
EDIT: What will the power-ups look like?