Rare's Battletoads (1991) is two things at once: a genuinely impressive, funny, great-looking beat-'em-up — and one of the hardest games ever put on a cartridge.

The toads (Rash, Zitz, Pimple) morph their limbs into giant boots and rams for comically over-the-top hits. Then comes Level 3, the Turbo Tunnel: hoverbikes screaming down a track full of walls you must memorize. It is where the vast majority of players' journeys ended, forever.

And the co-op cruelty: you can hit your partner. Friendships were tested. Controllers were thrown. Nobody who tried it forgot it.