Cyberdreams

Cyberdreams is a 1998 megawad by Gonzalo Pérez de la Ossa and Albert Valls. It is well known for featuring puzzles involving cyberdemons in each level, which the player is forced to solve without the use of weapons.

Overview
In all levels the pistol and fist are the only available weapons, and nearly all levels require the player to kill the cyberdemons. Often this is by using clever techniques such as telefragging, activating crushers, making the floor below the cyberdemon rise so that the height of the room it is in is not high enough to contain it and eventually kill it, and starting monster infighting between it and other monsters. Most levels require the player to activate switches while under fire from the cyberdemon's rockets (sometimes ridiculously heavy fire), or to dodge rockets while waiting for a crusher destroy the cyberdemons.

Level solutions
Warm Up: One on One --  This level places the player in a head-to-head confrontation with a Cyberdemon. To win, the player must lure the Cyberdemon to the center platform, then move through one of the four teleporters at the corners of the room to telefrag him. This must be done in order to reach the exit, as pushing the switch which reveals the exit activates a trap that captures the player, leaving him free for the Cyberdemon to kill.

The S-2 Factor --  In this level, the player must navigate barriers in order to reach teleporters in order to telefrag two Cyberdemons, while dodging their rocket fire.

A Bridge Between --  To win, four switches must be activated. The player must go back and forth across a bridge flanked by two Cyberdemons, which continuously fire. Hitting the switches will raise the floor sections to activate the sectors that will kill the Cyberdemons. The central bridge has a wallrunning capable sidedef that can be exploited. After going through the platform behind the Cyberdemons, they will eventually be killed, and the exit revealed.