While playing Halo IV I’ve had some problems with achievements unlocking. The achievement for ‘Reclaimer’ did not unlock until after I had completed the game and went to Mission Select. At that point, the achievements ‘Game On’ ‘I Got This’ ‘Can’t Put It Down’ ‘Bonus Level’ and ‘Up All Night’ unlocked, even though I have only completed 11 missions. The time in my Stats shows that I have been playing for 745 hours, an impossibility given that I purchased the game on Friday 20th. Is there any way to correct or reverse this? I must be looking like a cheat given that all of them opened within minutes of each other.