Konami's Teenage Mutant Ninja Turtles (1989) is beloved and infamous in equal measure, and the reason is two words: the dam.

You switch between all four turtles from a pause menu, and this is the part people forget: they share the quest but not the health bar. Each turtle has his own life meter and his own reach. Donatello's bo has the longest swing in the game and does the most damage, which makes him the obvious pick until he takes a beating and you have to rotate somebody in. Lose a turtle and he's captured, gone until you find him again. It turns your roster into a resource you spend.

The structure is ambitious too. An overhead city map lets you choose where to enter, and manholes drop you into side-scrolling sewers between the story stages. Konami was mixing genres here two years before their own arcade beat-'em-up port showed up on the same console and made everyone forget this game existed.

Then you hit the underwater dam in Area 2. You swim through a maze of electric seaweed, defusing eight bombs against a clock, taking damage from currents and contact you can barely see coming. The controls are heavy in the water, the timer is unkind, and a generation of rented cartridges went back to the store unbeaten.

It's worth saying the level is beatable and even fair once you know the route, which is exactly the problem: in 1989 nobody knew the route, and there was nowhere to look it up. This is what difficulty meant before the internet.

Brutal, a little unfair, and absolutely unforgettable. For a lot of us it was the first TMNT game we owned, and the cartoon-to-cartridge magic outweighed the rage. Mostly.