So interesting example here, if you pull up the frame counter when running Downwell on PC, it's actually locked to 45 fps upon initial launch. You can edit the config files so that it runs at 60 FPS instead, but I actually found this to be so much harder to play and score combos to the point where I rollbacked my changes to the initial 45 FPS.

When you line up like 6+ dudes in No More Heroes 1 and chop em all in half with one finisher slice and the framerate goes into the single digits and the screen fills with blood and money effects and they all scream 'MY SPLEEN' at the same time... ooooooooohh yeah that's the good stuff...!

The framerate tanking during max level mashup attacks in the Switch version of NEO: The World Ends With You oddly enough really helped sell the impact of the barrage of blasts the team strikes with from above. Also helps that it's not something that really interferes with execution that much.

An outdated example now because it doesn’t happen in subsequent remasters/ports, but Ninja Gaiden 2’s original release on Xbox 360 had an infamous staircase fight that slowed the console to a satisfying crawl: https://youtu.be/o34ZgIe-rp0

a classic example but imo nothing quite sells the sheer scale of the colossi in shadow of the colossus quite like the frame rate tanking as they consume the screen. any version where this does not occur is a failure imo

Earth Defense Force 2017 on the Xbox 360. When the framerate tanked it just fit with everything else considering the low budget visuals and 1950's sci-fi movie aesthetic it almost felt like a feature at the time lmao.

NieR (2010) is a bit of a loose example since the slight slowdown whenever you hit enemies is definitely on purpose, but the game would have actual unintentional slowdown trying to deal with too many enemies and particle effects at once, and watching the game stutter rendering the aftermath of a big attack or with every hit of your Great Sword as you carve through like, 13 Shades at once gives the combat some real OOMPH that the remake was missing imo.

Ninja gaiden 2 hurts to play on 360 the screen tearing is really horrible

My suggestion is Risk of Rain 2. The hook of the game is that you get items that give you power ups that interact with each other in interesting ways, and there's no theoretical limit of how many of the same item you can stack, and the game gets continuously harder the longer a session lasts, so things can get incredibly wacky. As such, tanking the frame rate is as more so a signifier of your ability to push the limits than it is a signifier of the limitations of your hardware. As an extension of this, I consider crashing the game to be a valid win state, and indeed, the most pure.

drakengard 3 of course

Can't remember if it ran "badly" but when Killzone 2's performance dipped, combined with the heavy controls, it gave it this incredible sense of weight that I found so cool. That game makes the PS3 feel like a machine rather than a sleek games console

also Kane & Lynch 2 cause that game's built to run like shit