Mothership is old classic from Pipeline (who also created wonderful 'Hell Station'). Mothership is a medium size space level where Duke has to survive from an alien ship. Design is good. Pipeline's levels were a bit ahead of time back then because they still look fresh. Especially the mothership looks amazing when you are looking at it from outside. Design inside the ship is quite small (tight design). There's also this nice shrinker puzzle (like in E1L4) where you must press some buttons once you get tiny. Gameplay is good and ending is a fight with Battlelord. So if you missed this level about three or four years ago then get it now.