Possibly the hardest game ever. It's the third installment in Capcom's Ghouls 'N Ghosts trilogy, released in 1991 for the Super Nintendo.
You're a slick knight named Arthur. Your woman gets nabbed by the universal bad-guy Sardius's pals. Arthur dashes off after her into the demon's nest.
This is the definition of a perfectly done 2d platform game. Modern 3d games can only dream of achieving anything this good. Arthur can toss a variety of weapons to the left or right of him. He may also run, jump, and double jump.
Perhaps the most important distinction/quirk to the gameplay is the way the jump/double jump works. In Super Mario Bros. you may change the direction of your jump in midair. In Super Ghouls 'N Ghosts your jump direction is fixed, though you may change direction on your second jump. Jump control comes mostly through controlling the height of the jump and careful use of the second jump.
Damage is taken by running into a baddie. One hit causes Arthur to lose his armor (regardless of which armor he had). Your boxer shorts are poor protection from the demon horde; getting hit when you're half-naked will turn you into a pile of bones.
Outstanding graphics for the Super Nintendo. The sprites are well drawn and the levels add to the general spooky feeling of the game. It even makes use of Mode 7 for several parts of the game.
Here's what really takes it away. The score and sound effects are amazing. Unparalleled. Spectacular. The music throughout the game is spooky, captivating, and comfortable. Comfortable? Yes, you'll be playing the same level a lot... this game is tough. The music is intricate yet subtle. Best sound effect: reclaiming armor when naked.