The weird lighting in ISV-Kran didn't help to fix how fail was its atmosphere in the first two maps. Bright and lots of colours. It was just a (boring) Skaarj slaughterfest, nothing else.
Would have been cool if the Pupae really appeared out of nowhere and if the music doesn't make you realize about the presence of Skaarj waves.
The only exception is ISV-Deck 1 - has the best music of all the three, the Bloblets, nice set of battles, the beginning with all the Skaarj and the observatory room where you're ambushed. Since it was made after ISV-Kran-4-3-2, Myscha had more knowledge about doing something better
I don't hate the first krans, that much, in the first map the fight was pretty atmospheric, without music there wouldn't be a bit of adrenaline in there, it's not about the scaryness there, as for the deck1 I hated the seemingly infinite waves of skaarj in the beginning, forces you to run through it at your first playthroughs. Which was different from the previous Krans.
I still prefer the original krans over the 7B ones, even if they were made scarier, they were just using the method of triggering loud sounds which make you jump, it gets old after while, but still except for the intro cutscene which was really crap, it was better than the rest of the pack....
Vortex was always the most atmospheric, you can hear even some other sounds if you stay at area for longer time, such as the security team to sector..etc sounds, though too bad there is unused the forcefield activated and deactivated sound, I remember in the beta I played back in 98, there was acgtual forcefield, it was down in the prisoner rooms, there where is in final version the lift leading down to the electric chair room, but the wall wasn't closed like in final, instead there was this forcefield and behind it monitors and stuff, I think even living humans, I didn't discover there was this lift, so maybe after you electriocute that guy and do something down there, the forcefield goes down?
In the avaiable beta there are also used the access denied and permitted sounds....but not the forcefield ones as the door is closed permanently in the area where it originally is..