If anything, this sample size seems small based on the contextual commentary from both Game Informer & IGN.
Maybe this is just hopeful thinking but this only furthers my view that the campaign will be closer to 14 - 18hrs and possibly longer if you 100% the open world.
Ign said they never even reached skirmishers etc, and still referenced other inhabitants they hadn’t seen, 343 would of only allowed a portion of game to make sure some spoilers aren’t accidentally leaked etc.
If they got to play for 4 hours I’m pretty comfortable it’s gonna be a good length, Joseph Staton even said it’s the longest Halo game to date.
“4 hours” with the game doesn’t mean 4 hours worth of campaign.
They could have have 1 hour worth of campaign they were allowed to play for 4 hours.
I know that if I was an early access tester, I would stretch every minute of content out to the longest I could.
Edit:
I’d like to point out the lady they got to play the game said she is an “Explorer” type, and also mentioned she didn’t get many objectives, which sounds like she went Skyrim rogue. Got the main quest and immediately ignored it for side stuff.
I imagine the main story to be probably about the same time frame as a regular Campaign, but if you do all the side missions and go for 100% it’ll be significantly longer.