Well, I gave up after around 10 hours. It was just too hard for me. I never got out of the first biome, fought the first boss three times, died half way through each time.

The pros:

Looks fantastic, if a little dark. The environment is second to none and the atmosphere is palpable. I was engrossed immediately and felt the immersion. Even the obvious power ups etc just seemed to work. I felt at one point that I was in some sort of game (within the game) which was a weird feeling but the immersion was rarely broken. The action is intense and the gunplay is very satisfying. The gameplay loop is a fantastic idea and the ever-changing layout works well. Score and audio was superb, at least what I heard of it.

The cons: it's really just the progression system for me. I figured the game might be a bit more forgiving and the algorithm may take pity on me, but it didn't. Each run felt satisfying and different but it started to get to the point that I just wanted to progress. I had five or six runs where I didn't progress from the pistol. Only maybe five runs overall where I had something that felt a little better than a pistol, but ultimately it was like being stuck with the Doom pistol for 15 hours. Sometimes I felt like I had a decent run but then would get into a lockdown and get annihilated. Sometimes I'd get a malignant thing and just suicide because it was annoying. The element of randomness was just a bit too much. I'm sure there's some emergent gameplay I'm missing, but I felt stuck between a Deathmatch and a Story, and couldn't get out. There was also a heck of a lot of info to take in.

Conclusion: I think, ultimately, I'm just not good enough or patient enough for games like this, and I don't think I worked out the plan to get to the boss. I wanted to get a fresh run and be able to just power through everything but I couldn't, previous runs never influence subsequent runs that much in the early game. I enjoyed my time, I'd love to play more, but I just can't take beating after beating like that.