Co-OP missions are fun,  but if you're as impatient for MP weapons as I am, try this:

Eleventh Hour Mission (last one) on Easy,.

Just run straight through, get to the bomb, and fail the disarm.

An easy 4600 point average in as little as 38 seconds. Stick to the right side of the first room, jump down escalators, and jump when a jump dips down to stab you. Shoot the last guy just outside the subway car, as he got me often.

Don't even need both players present. Host can reload and do all the running.

Ran this with chud.  You could max out in roughly 2-3 hours

As of the December  patch, the required points for getting ALL unlocks went from 441,000 to a mere 160,000. I just went through all 6 with Yupitsme and after doing all 6 CO-OP missions, it only took about 25 minutes of farming to get him the required 160,000. So if any of you that were too impatient to do this, it's MUCH faster, now.

And the unlock weapons are certainly worth th effort.

Talking about exploits and glitches goes against the core values of BK. Can't believe this thread wasn't deleted when it was originally posted.

You get points when you die, no matter what. You just get more if you make it to that point in the mission... it's not a bug or anything.

EDIT: There we go.

Well the CO-OP missions are absolute rubbish and the whole CO-OP concept stinks.  I don't think it's an exploit because it's not hurting other human players.  All you're doing is getting that G3 unlock anyway.  Not hurting anyone in my opinion.