Count me among those who don’t think the OP is being unreasonable. He had:
Accommodated the roommate on weekday/schoolnights
Rearranged his space to avoid too much light affecting the roommate
Used headphones to cut down on noise affecting the roommate
Offered to set a defined sleep time (presumably of reasonable length, at least 8 hours) where he will not use his computer
Cut down on basic necessities like drinking water to avoid annoying his roommate
and the roommate is making NO effort to work on a compromise.
Obviously, the OP should not be up all night gaming. I would even suggest that setting an extended “quiet time”, say midnight to 10 AM on weekends, is reasonable. However, the roommate seems to want the world to revolve around whenever he wants to sleep and if he needs to sleep for 14 hours then nobody else should have any rights. Certainly, if the OP were having people over, playing loud music, or gaming without headphones it would be different. However, if he can’t even get a drink of water or go to the bathroom then the roommate’s demands are affecting the OP’s health also.
Seriously, though, in what dorm do you live where anybody could even hear a keyboard over the sounds of the students in the other rooms coming in drunk, slamming their doors, laughing and talking all night or having sex (yes, I’m talking about you Anne who had the room next to me Junior year when I was studying for MCATs-you and your BF were LOUD!).
The way I see it though, you have 3 choices:
#1) Sit down with the RA and work out a reasonable compromise in writing, such as no gaming from 12-8, but you have the right to drink water, go to the bathroom, etc as long as you keep it relatively quiet. This is where you get the RA to suggest that the roommate purchase a white noise machine or consider earplugs, but I would not buy them for him. You come to the table and say “These are the accommodations that I am willing to make” and let him adjust to live with them.
2) Pursue a scorched earth policy and do whatever the hell you want. Have friends in all night, get drunk and throw up on the floor in front of his bed, have loud sex in front of him, While not recommended and of course something I would never ever do, I will note that Sophomore year I technically lived in a double room by myself. Yes, each semester started with a roommate but somehow they never lasted more that a few weeks and the double room was mine from then on. (Although the fact that there was no shower and only an ancient clawfoot tub for bathing in might have had something to do with it-I loved it and couldn’t understand why the roommates kept grumbling about having to shower at the gym when I was enjoying my luxurious bubble baths-yeah it was a weird dorm (old converted Victorian hotel and the other rooms all had private baths with actual showers) but I thought it was awesome).
#3) (This is the one I recommend) Suck it up and give in. It’s only a few weeks and it won’t kill you to give in until the semester is over. Some things aren’t worth fighting and when you move out on your own you can do what you want. As a fellow night person, I have to tell you that morning people are favored in this world and it’s a lesson to learn earlier rather than later.