I just finished the campaign on Heroic 1 skull using only 1 weapon the entire way. 6h 32min. So what if it is the most OP weapon lol. Still made it.
I could probably do this faster I did some open world stuff I didn’t have to.
cool time, man. 
i finished a 100% legendary playthrough in about 28 hours. not too impressive, but right under the average 30 hour campaign time.
What weapon was it? Asking for a friend.
The secret cannon at the begenning. Lol it shoots tank rounds
Oh not seen that, will check it out 