Step 5: More other tips
Teamwork is vital. A group of average players working together (who use this instructable) is very challenging for a group of independant players (even if they do use this instructable).
I've also found that players with funny gamertags are actually pretty good at this. However, players with Halo related gametags are really good, so be prepared for a tough fight.
I have to put this cheat as it is too good to miss. For the special, extended ending, you need to beat the final stage in Legendary mode. The final stage, not the rest of the game, but I suggest doing it normally first and then in legendary