UDOB6 - Released for Copper Quake on June 20th, 2019
Ch'thon, Quake's only boss to speak of, is not so much a boss as an environmental puzzle: a huge but immobile demon who lobs endless explosions at you while you run laps around him, hitting buttons that lower big convenient electrodes to zap him to death with; repeat if necessary. Since one of the goals of Copper Quake was "no new monsters", if I didn't want Underdark Overbright to end on a whimper, I had to revisit Ch'thon and find a new expression of the puzzle possible solely through level design.
Kell MacDonald accomplished something similar in Contract Revoked. He treated the boss room as a hub (one with a big angry demonic turret in it), building a unique wing of the level to prefix every zap of the electrodes and fusing the three-round structure of the "battle" with the three-lobed structure of the map. I took a similar approach, keeping my three annexes short and dangerous to maintain the propulsive momentum of the boss room through the side chambers, in contrast to Kell's more pensive challenges that lend his Ch'thon fight an alternating rhythm.
The player has the almighty rocket launcher by now, so the power curve has been established, and since Quake custom singleplayers typically only feature the RL for pacing reasons right before they end, if at all, I wanted as many excuses for rocket action as possible. Besides providing respawning rocket supplies around the arena, I also start the player face-to-face with enough boxes of rockets to completely fill their inventory, a classic trope of using intentional excess to signal that hell's on its way. I went a step further and borrowed the convention of rocket-impact-activated switches that served as a central mechanic in czg's Honey, using these as triggers for the electrodes instead of touch-activated buttons.
This is a simple change, but alters the feel of the fight considerably. Rather than just nudging a button, which can be done as an afterthought, the player has to plant their feet, line up a shot, and fire a rocket into an opening, while under fire from a huge immobile demon, evoking a repeated feeling of sinking a three-pointer at the buzzer (or firing a proton torpedo into a small thermal exhaust port while the rebel base is in targeting range, if you're not into basketball). I also cheated in some extra sound emitters in key places, to guarantee a good solid 'kachunk' was audible to the player whenever a rocket connected. Since I hadn't used these switches at all in the episode up to this point, they had to be taught, so the last step was an initial rocket-switch-activated gate to prevent the player from entering the arena before 'doing the thing.'
The result is a boss fight that has the intensity of a multiplayer deathmatch. I exploit narrow sightlines to ensure that players can only shoot the switches that lower the electrodes from the upper level of the arena, but can only shoot the one that activates the 'zap' from the lower level. This sets up a cycle where the player has to enter and clear out one of the side pods to gain access to the upper level, then drop back down for the payoff each time, so they can't just run the circuit. It also adds an extra insult to the injury of being hit by one of the boss's projectiles: being knocked down to the lower level means having to retrace your steps at best, or landing in the lava at worst.
I underestimated the difficulty some players would have with making precision rocket shots while under fire. It's a very skill-based test compared to the generous size of Quake's monster bounding boxes, where usually firing anywhere in the general vicinity of a monster is good enough to draw blood. The design necessitated the rocket switch openings to be fairly narrow, to limit the angle from which they could be tripped with a rocket and prevent sequence-breaking, but this introduced a skill floor that some players felt excluded them. This was exacerbated by the fact that some Quake players play with the crosshair turned on, and others with it off.