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| IMA FIRIN MAH LAZAH!!!!!! BLARRGHHH
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It is like the horde mode in Gears Of War 2. You keep fighting the covenant in hordes, while random skulls turn on, I don't think anyone knows if the hordes end at a certain number or keep going for ever. Also there is a number of different maps you can choose Bungie has only told us of 2 so far.
[Edited on 06.28.2009 11:24 PM PDT]