I think Quake and Quake 2 returned to the more serious take when it came to level design and atmosphere. I think in addition to the difficulty of game balance the level designers decided to have more "fun" with their designs instead of trying to keep a certain atmosphere. You're not forced to keep throwing more and more monsters at the player. With an episodic game the difficulty level can ramp differently, you can restrict weapon and item sets more effectively, and you can change the entire look of the game between episodes.
It's a difficult task to balance difficulty and challenge against not overly frustrating the player. You have to keep the player challenged, but to do so you have to either make items scarce, increase the number and difficulty of the monsters, make the level geometry more forbidding, or some combination of the above - The Living End being a prime example of the last of those. I think part of the problem was the change from being episodic to a linear progression. Doom 2's levels do feel somewhat gimicky. Originally posted by Phoenix:The level design in Doom 1 was absolutely superb. That's not to say I don't enjoy Doom 2, but I still just love the original more. I think Quake and Quake 2 returned to the more serious take when it came to level design and atmosphere. Doom II adds one new weapon to the players arsenal the super shotgun, several new demon types with more advanced attacks than those of the first Doom, such as the chaingun-toting Heavy Weapon Dudes, the skeletal Revenants who launch homing missiles and the sinister Arch-Viles who have a highly damaging fire attack.Doom 2 is definitely a. The level design in Doom 1 was absolutely superb.