This is map 4 out of 7 of my current personal project, Tomb of Thunder. Named Dissection of a Concrete Body, it takes place at the facility seen right at the end of the previous map, No Rot In The Cold. After having to restart the Reactor Core, progression is semi-open, where the player has to look for 6 Gold Keys throughout 3 levels to open the final room.
This is the second longest I took to make a map for this, which is 4 months.
Tomb Of Thunder is currently a work in progress.