One day? That’s optimistic. I did it coop with my wife, we give ourselves one day per MISSION. Sure, I guess you could try to cram it all in one day, but after grinding through one mission, we tend to just need a break. LASO requires thinking the level out and making a plan, you’ll likely end up being force to play levels in ways you’ve never imagined before. We’re actually still working on it, so I can’t speak to the difficulty of The Library and beyond, but:
POA took like one hour, mostly because it was our first time going into LASO and took a while to get used to, but once we had it down, we were able to get through it pretty easily. We skipped some of the harder fights like the stairwell using speedrun strats.
Halo took a good four hours, there were some spots where we would just be constantly surrounded and it took a descent amount of planning and experimentation to figure out exactly where to go. Turns out, you can pretty much bypass the wave of phantoms because the AI’s navmesh doesn’t extend to the entire area and and the light bridge fight can be snuck around, but not in the same way as speedrunning. We killed the marines instead of the covenant because the game only requires you to actually fight one out of the three groups.
T&R took four or five MONTHS. Not Yoinking! you, we probably attempted and failed it twenty times. You have just barely enough ammo and if you run out, it’s mission over. You can’t run past the enemies, nor are you in close enough quarters just beat them all down. Keyes will always stick to player 2, which was nice, but I don’t know how anyone could possibly beat it single player without Keyes dying. You’ll probably need to learn a despawn trick. Our final stream time for the end of the mission was about 5 hours.
SC was nothing, took less than an hour. The entire trip down can be skipped by jumping down the shaft, and most of the trip back up can be skipped with the camo.
AOTCR takes 20 minutes, the speedrun strat works.
343 is also nothing, easily less than an hour, the only difficult part is the final section, but taking a wide path tends to keep the flood thin. Make sure you know how to end the level as quickly as possible (kill the sentinals.)