Well,it is good, in fact one of my favourites,its short and really really well structured with a good topic,I'm aware that I mentioned this before,but I want to talk about it a bit more to explain why is better than TNTNE(well,personally).
For a quick reference that can explain my thoughts I will compare Mareway and Hurst with Portal(the first game,not the fanfic,in case that there is any fanfic with Portal theme),Portal was short and its was really interesting because there wasn't too much that can be known,it didn't need too much background for each of the characters and the actions made the story,the same can be said about Mareway and Hurst,while TNTNE is more like Portal 2,its good but its doesn't have the same impact and it has to create some background for the character in order to work,which makes the story a bit tedious sometimes,not that is bad,the problem is,is not as good.
BronyCray's writing for this one is spot on,it really does give you some immersion with the context,the story is more related to his writing style and its better presented than TNTNE,why?, because its short,but its also a bit grimdark,and its well paced to keep you intrigued,which is something that I never manage to grasp so well in TNTNE,apart from that,I like the style of it,and the delivery,is really well put together.