Wow. Wow. Wow.
I thought that was going to be FUN. Turns out it took 5 **** HOURS. SERIOUSLY.
Okay, imagine this:
There's a canyon. The canyon is roughly 5 minutes long from side to side when sprinting. Imagine killing 85 people on each side every 5 minutes, and imagine doing that 100 times. (I'm not kidding, there's 20 rounds which have 5 waves of the SAME **** THING).
And here's the terrible part, after about wave 10, it starts lagging because Borderlands doesn't make the limbs of your enemies disappear when you kill them. So here I am, wave 20, and I can't look anywhere except for the ground without the game's framerate PLUMMETING because the place is filled with so many arms, legs, brains, bodies, carcasses, dead guardian alien things, etc.. I hated it so much. It took me 5 hours of the same crap over and over again.
I also hit level 49, and got to around 2/4 the way to level 50, which will give me an achievement.
There's two more of these arenas to do, but they're both considerably smaller. I'll just go ahead and do one every day. Doing 12+ hours of work tomorrow is going to be hell on my patience. At wave 10 on this one I was already like UGH I'M SO BORED.
Oh well.