So me and my brother just spent a little over 5 hours playing Sudden Death Blitz. By the end of it it just became an endurance contest. We wanted to try and reach the number 1 and 2 spots on the leaderboards for overall, which we attained and I'm quite happy about it On a side note, with a good enough strategy you could potentially go on forever. We got to 1500 rounds, set our controllers down and let the turrets go for another 27 rounds by themselves before losing. It's not really a complaint, just sort of pointing this out that once you get a strategy, since the difficulty doesn't increase after wave 60, you could go until you burst. This aside it was really fun, anyone who hasn't tried this gamemode yet should.
We used a Tank and a Support. I know that's not really anything top secret seeing as how you can figure that out from the leaderboards but finding the strategy that works is half the fun, trust me Just remember that product grenades are your friend!