Mothership

The Eternity Engine has a steadily expanding set of features that position it in my mind as "prBoom+ with spice." It can do vanilla-through-MBF emulation and retain a similar in-game feel, and it has portals, a MAPINFO analog, a content definition language that stretches far beyond DeHackEd, and more. It even has a scripting language. 

Mothership drives that home, especially if you have played Ancient Aliens. It captures similar design ideas and feels Boom at heart, but through extensive use of portals, it renders a multi-story spaceship one could normally just hint at. Outside the windows, sector-architecture UFOs don't hover statically but glide around in the emptiness of space. It's a sorcerous effect created with polyobjects and scripting. 

Beyond the bells and whistles, the core elements of Mothership hold up okay. Deliberately idling underneath skillsaw et al.'s shadow makes it easier to notice faults and underachieving: Fights that can be slick and entertaining but rarely flesh out their ideas all that thoroughly. Visuals that are clean and eye-pleasing but are sometimes dull, not a function of lacking detail (the "quantity" is similar to Ancient Aliens's) but of limited contrast, of low variety in design motifs. My favorite nuance comes up later on, in a messy brawl with archviles perched high above on a 3D floor platform. Instead of hugging the outskirts of the arena, you can hide under these archviles, too, remaining fragile and in the fray.

3.5/5, minus 1 for using stars.mid, plus 1 for using stars.mid. 

0/5 for the overrated music track

5/5 because I played this on the easiest skill setting because I suck at doom and yet the map still managed to be fun and surprising and gave me hope for what is possible to make in the eternity engine