Shows a way to bypass the keys and reach the exit area somewhat faster in Doom II level 11, Circle of Death ('O' of Destruction).
This involves using the edge-activation exploit on the switch that lowers the barrier blocking access to the northeast quadrant of the map. Once it's down you can Strafe-Run across the gap to the platform leading northeast. (See https://youtu.be/mq-VUpLAaww?t=33 for a video showing how to open the exit chamber once you've reached that area.)
Note that in this video the player grabs a radiation suit to avoid taking damage from the slime, but that too can be bypassed (see https://youtu.be/aNmgktag5Ec for an example).
Doom II: Hell on Earth Statistics For Classic DOOM
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