first things first, the maps just work. and not like how Todd Howard means it but it just works in general. i never seen through the map or fell through it or seen a missing texture or something overlapping. it was a great experience.

there has been much said about the maps but i'll just focus on the secret level.

the way you get there is by a chip in one of the levels. something about a temporal anomaly. if you played it then you know what i'm talking about. if you haven't i'm not spoiling anything.

i was certain by the way the room is set up where you can find the chip that it was supposed to be a switch puzzle. a certain order to flip the switches and the way becomes clear. its not, in the end you just flip one hidden switch. the others don't matter. it was... unexpected. but serviceable. kinda a letdown in my mind.

the second part is to find a slot to put the chip in of course. i figured out that it wasn't on the level that you get the chip from as i looked everywhere for the hidden switch. (which turned out to not be all that hidden) i was surprised that this 'temporal signature' stuff doesnt get mentioned ever again. i dont know what that was about. and really the only way i found out that i could even get to where i needed to go was that i got blown up one time and flew out the window. normally when you jump out a window you die when you hit the bottom (suffocation) not here though. i cant imagine how i would have found the chip slot.... i cant say that i agree with how hidden it is. again, why didn't the creator put in another hint like with the chip?

anyways, the secret level itself. a nice, very nice, doom 2016 like level. looks like an 8 on its side from the top. some elevation and plenty of spaces to hide. you get loaded with ammo for all your guns. plenty of fodder enemies to use the rocket launcher on. it was very enjoyable to blow my way through everything.

TLDR to get to the secret level is hard and inconsistent (introducing a temporal signature gimmick for a hint but then not following through with it) but the secret level itself was awesome.