the first run was so much fun already. really great job!!
but we could jump out of the black base before the start at the corner ^^
also, please make the winning/kill count bar smaller, but tbh i am not sure if it is scaleable lol i did not try i think 
there were RMs just standing in the base and buffed the players, sadly they did not get any rewards now lol. it seems if you dont dmg/hc and only buff, it doesnt count as participation.
well, many did not understand they can use the buff pang and sometimes just ran out of the base without buffs^^
i suggest to boost the buff pang a bit, make the model larger and give it a different name, so everyone will understand they can use it even with their high level.
the red circle from Kalgas attacks was barely visibvle, pls make it more visible.
also, now we were many participants because it is a new thing. but in a few months there will be less and less participants. so i highly recommend doing (middle of the screen) server shouts shortly before registration phase ends and before enter phase ends. also add this shout in the chat box (like the messages "GM will never ask for personal ID") so more players will get reminded of the upcoming Kalgas fight.
This gamemode NEEDS many participants to work out well.
by the way, you do a shout 10min prior rainbow race, but pls add this to the chat box too. its just in the middle of the screen but u miss that fast.
idk, maybe add some black and white monsters which are spawned at the same time by Kalgas more or less randomly, going around slaughtering the opposite teams.
add a map to make it easier to communicate with your team which artifact you might wanna backdoor and take back, add a message that the enemies team has taken over your artifact number X like "you lost artifact x" and "your team conquered artifact X"
8)....20)
damn the more i think about it, the more ideas i get. this can be THE GAME par excellence