Surviving Marathon's latest map, Cryo Archive, is one hell of a challenge. Completing all the puzzles and the pinnacle event, a boss fight against Compiler, well, that's on a whole other level entirely that we mere mortals can only aspire to reach.
You need to gather six rare keys from the other maps to open the corresponding vaults on Cryo Archive to collect a unique subroutine item, and then challenge the Compiler. Of course, it's even harder than that in practice, since you could get killed and lose your keys, or even open the vaults but get unlucky and not have the subroutine spawn. Thankfully that last part's being fixed, and subroutines will have a 100% spawn rate starting this weekend.
