Duke Nukem Forever 2001 - Warp Zones
A few DNF 2001 levels made use of Unreal 1's Warp Zone technology (as seen in the deathmatch map DM-Radikus) to connect different parts of a level to make them appear as if they were physically connected even though they're not. Pawns and projectiles can pass through the warp zones seamlessly but hitscan weapons can't shoot through it.
The bike canyon map (Z3L1_1) is also similar in that the parts of the level are all physically unconnected, but it uses the Transporter actor to seamlessly teleport you to the proper level part instead. I'd show it here too but the transporters only react to the bike and I couldn't figure out a way to dismount the bike (which doesn't let me noclip).
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