Valve's Portal 2 is a ripe playground for modders, with a simple core concept which opens up into a Pandora's Box of puzzling elements, so it's not surprising they can sometimes fall down a rabbithole of development themselves.
Read more: Best Skyrim mods.
Repercussions, a single-person mod project currently into its fourth year of development, is currently deep into that warren creating a single-player campaign which mirrors the second-half of Valve's 2011 sequel.
Though mostly the product of one mapmaker known by Lemurr, part of the award-winning Portal Stories: Mel dev team, there are bits chipped in from concept artists, modellers and what sounds like an excellent soundtrack from composer Kevin Alexander Baggett.
Of course, the downside to a one-man show is the lead times on absolutely everything, as Lemurr notes in the mod's latest update last week that he's far from finished and that we "shouldn't expect a release any time soon."
However the upsides are numerous, including the almost perfect recreation of the atmospheric, spooky environments in the cavernous remains of Aperture's testing division. The travel through time aspect of Portal 2's second half has also been preserved, even going as far as giving the player a more retro-themed Aperture portal device than the one Chell gets.
There's also been some obvious influence from recent games that nailed the same retro-futuristic aesthetic, such as this nod to Alien: Isolation.
It's all the more impressive if you check out some of the earlier work-in-progress video tests from 2012. In all it looks like a mod good enough to wait for, and has made me pine for Portal 2 so much that I'm reinstalling it right now. That's a good sign, right? Let's hope development continues smoothly, if slowly.