But, speaking of Red Eclipse, I would love to see an arena style game mode be put in.
However, I don't want it to take away from the parkour aspect of the game. Red eclipse is an Arena-Style shooter first that has parkour mechanics implemented. It's parkour is very simple, basically limited to wall-running and sliding. Celaria was built from the ground up with parkour in mind, so this could make for a great base for other types of game modes!
So basically, I was thinking maybe more like an instagib sniper sort of thing. The game has potential to make large maps for traversing, and ideally could serve as a parkour-style arena for people to battle in.
The time-trial game mode would still be a big aspect of the game -- but going in, battling some people or friends worldwide or locally could be really cool.
As far as design, I was thinking that there would be a drawing and holster button, namely 'F' or 'Q'. When a weapon (I was thinking a sniper/pistol) is drawn, some movements would be limited, like frontal wall runs, and ledge grabbing (obviously because you have a gun in your hands), but things like horizontal wall runs, sliding, rolling, etc., would still be possible. In my head, I imagine doing a horizontal wall run and looking over to quickly snipe someone on a lower platform. Shooting would use LMB, and Zooming (with a rifle or sniper) would be the RMB, with scroll to switch between weapons.
Some melee combat could be implemented too. The characters already have claws on their hands and feet, so maybe you could implement some simple melee combat (claw swipe and leg kick?) that wouldn't hinder someone from moving regularly.
Also, a couple of more movements (namely, shimmying on ledges and dropping straight down from one) would be nice.
I would like to hear what you think, Lewa, and would be happy to help with any testing in particular. I really hope you consider this idea, as I feel this game has a lot of potential for multiple game modes.

EDIT: So, I played again, and I'm getting a real good feel for movements and things, but one thing I was wondering was whether or not a better system for walljumping between walls could be implemented? I can sort of do it with the current method, but it takes a lot of focus to aim at the opposite wall each time you jump off it. I was thinking that maybe instead whenever someone jumps facing against a wall, the camera would automatically rotate 180 degrees to face towards the other wall.
DOUBLE EDIT: Ignore that previous edit, stupid idea.