Yeah, that ending was over the top. I mean, shooting a Portal to the moon? That was just ****ed up. The whole Manual Core replacement ritual made me laugh the most out of the game tho. GLaDOS and Wheatley can be soooooo dramatic.

As for co-op, me and Rage are almost finished with it, we literally had to stop at the last chamber out of the last part of the whole co-op because Rage had to go. There’s not much of a storyline attached to co-op, besides GLaDOS stating that ATLAS and P-Body were created to develop human feelings and once those start showing up due to the huge amount of cooperation needed during the tests, she starts attempting to create petty fights over them, in the most famous GLaDOS fashion.

But there may be a hint for some co-op exclusive storyline: it’s usually 4 steps for testing in co-op: Teamwork, Mbum and Velocity, Hard Light Bridges and Excursion Funnels, but once you complete Excursion Funnels GLaDOS announces she has a surprise for the robots and open up the last testing co-op chambers, which tests Repulsion and Propulsion Gels (as of now, middle of the last part, no Conversion Gel has been used, or spotted), and like the single player mode, those are located in the old Aperture Science headquarters, but with GLaDOS being the announcer this time. She also taunts you about keeping humans prisoners at the end of the Gel chambers.

Some of those tests in co-op were excruciatingly hard, even more than the single player at the first runthrough. They can get VERY frustrating after a while, but it’s usually something really idiotic to solve.