Dirty and whimsical, Sisyphos is like Alice in Wonderland meets Detroit? Maybe it's the abandoned sticker-bombed van that takes my mind to Detroit, and the mini creek and fairy disco lights that makes me think of Alice... Over one weekend, I got into the club two times out of three (the second time, the line was way too long and my group bailed). My stamp from the Friday night was honored Sunday evening, so shower gingerly if you enjoy paying reduced cover (15 euro initially, and then 5 for re-entry). The staff here are a little nicer and less intimidating than the guys at Berghain, but I think the overall lack of showing positive emotions is a largely German thing. Additionally, if you don't speak German, hand the first bouncer your phone for stickering, and ID if they ask. Get patted down in the second room, pay your cover fee, show your stamp to the last doorperson, and stroll through the final eingang into Sisy.
At the beginning of the weekend, only three rooms seemed to be open (tech house, darker house, and disco) and then closer to Sunday/Monday, an additional room opens up to play more tech-house, as well as the rooftop bar behind the abandoned van. Sisyphos has plenty of places to sit and chill if you're getting tired of rotating around the rooms. Stay past sunrise, or leave whenever you please.
Bathrooms are grungy and unisex. Toilets are awkwardly high or maybe I'm just terribly short... Lastly, if you're a germaphobe, don't come sober, pack napkins and hand sanitizer, and leave your worries at home.