Well if you played any of the mods (i.e Rocket Arena 3) then this is exactly the same game as Quake 3. Cloan Arena is an exact replica of RA3. the only difference is the consistent development. The physics in the game are almost identical to Q3 with a high majority of the maps coming from Q3 and its mods.
CA is vastly different than RA3. Did you play it once?