Salamander's third boss can be counteracted by
shoving your Vic in his mouth. (fresh credit @ full defaults, PS4 ACA ver - works on PCB, MAME and the PS1 conversion, too) This'll lock up his blue balls, greatly relieving pressure down below and allowing you to secure a prompt climax. Note the handy orange lines just under the core - you can get close, but don't go beyond, or you'll explode in his face.
Don't ever do the ol' "play a credit, die at the st4 boss, then start a new credit and it won't shoot" trick. My pastor told me you go to hell IRL for that.
RE thread, I like Silent Hill 2's enigmatic red square. Elegantly creepy, with their strange reflective quality, and James's unsettling comment at his first encounter with one (
"Feels like someone's groping around inside my skull...") - and the climactic instance is a nice bit of optical trickery. Was used as the cover of the NTSCJ PS2 release, in fact.
Sorry SPM

Take heart - GEARSHITERS will become forum legend, I am certain!
Seconding Rastan, Sumez and Hypnos. My mission is to kill these motherfuckers by any means necessary.

If the devs leave a bunch of handy exploits lying around, that's a shame, but it ain't my problem.

The essential joy of hardcore is "How can I survive this?" What are the enemy's capabilities and weaknesses? What are mine? How about the terrain, Rank, useful audiovisual cues, etc? My favourite arcade-styled games demand this sort of close, active analysis. Sometimes things break under scrutiny.
Like DMC, I make a distinction for pattern design that's clearly meant to accommodate aggressive, learned attack. Remembering a lot of such instances in Raiden, getting back up to speed with the ACA version this week. A blistering precision-machined shitstorm with a nice ship-width aperture to dart into for pointblank speedkill fury (at risk of getting shredded yourself, if you're sloppy) is quite different from the stultifying
Amazing Shump Gameplay of legend. (I am so delighted others remember that video

)
Speaking of Salamander, I don't necessarily dislike stuff like its famous third stage pleasure cruise through the raging bowels of hell. That shit feels good, and looks+sounds
AMAZIN 
In those cases, a safespot can feel more like a breather than an exploit.