In the Doom-era game Rise of the Triad, if you shrink the viewport all the way down to postage stamp size, it displays "Buy a 486!" underneath.

ROTT uses the Wolf3D engine and was somewhat of a collaboration (if you could call it that) between id and Apogee!

ROTT is in my childhood's "badass games hall of fame" along with Quarantine (aka Death Throttle aka Hard Rock Cab), Abuse, and Stratosphere. Honorable mention: Microsoft Flight Simulator: Aircraft & Scenery Designer (MFSASD) for the ability to make an almost flyable U-2 from the jet plane.

dipstick gunfinity burnme

DOOM was playable on the 486SLC2 with a modestly smaller viewport despite having just a 16-bit bus. It was the one donated IBM box in my high school's computer lab that could play it because Model 25 and 30 286's sure couldn't.

they can now though, there is a 286 port for 640k which even does cga and mda next to the initial ansi shaded text mode