Um.....all of it I suppose? But if I just had to choose one for the hell of it, I would go with kicking the purple orb off the tower or getting the bunny emblem from finding enough crates on the moon (simply because I didn't see anyone else with it). Not any amazing highlights I can think of really. Did the strike on hard practically solo, had one other in there but he just ran around dying, think he got 2 kills by the end. Didn't feel super accomplished from it though as I pretty much had it down so well I could do it in my sleep (played too many runs through it I think). I was happy with my average K/D on crucible, and found tons of grimoire and ghosts so all in all I just had fun.