You can replay your favorite missions again,you could go beat the side missions to get achievements and get bonuses also 100%,you can go buy the rest of cribs and cars that you have yet to get.Or you can go on a rampage if your bored.There are those hidden item things you can get for 100%.Honestly there's alot of stuff to do after you finish the main story.
beat them
You can't.
by beating every main mission.
Depends what mission your stuck on. Go on halopedia they have walkthroughs of ever single mission
find all mission idems. beat every mission, and find information about G, the gaget guy.
you beat the entire story mode then you need to buy them from shops and do EVERY single side mission. or you can always look for cheats...
After completing the mission in the jungle, you have to complete every dispatch mission.
get EVERY item, do EVERY mission/ mini mission, do ALL the gummy ship things, beat the game QUICKLY.... >_>.... it was kinda hard to do....
probley yes.
nope you end up living a better life and there is a secret mission where you have to kill julisu after the game is beat
You beat every mission, but you have to be a noob.
every time you beat a mission you get guns. i wish there was a cheat to get them all enywase