In a Nutshell: A seemingly run-of-the-mill racing game based on the real Paris-Dakar Rally, which includes light adventure elements at the beginning when you have to get a car sponsored before the race.
Legacy: Not much of one. Paris-Dakar Rally is a rickety game, for lack of a better term. The main "race" stages are typical top-down, vertically-scrolling affairs, with track design that never goes any direction but straight, and a tendency to have opposing cars rush up from behind you, frustratingly taking away a try when you least expect it.
But as mentioned, it was only seemingly normal -- as soon as the second stage, the game turns into a platform action game, with your rally car now able to fire small bullets at enemies, and you as the driver able to exit the car and go go exploring to lower a bridge or bypass other obstacles.
On top of that, the next-to-last stage goes back to the top-down view, but now you must avoid a fleet of tanks and fighter jets. A game that looked no-nonsense from the start quickly turns into a farce.
What to Consider: Going against the real world's definition of a car or any vehicle can easily be the core of a unique game concept, and also easily proves the power of a video game’s ability to combine wild imagination with genuine interactivity. Paris-Dakar Rally had contemporaries like Blaster Master, with its jumping-and-shooting four-wheeled tank; that game became a classic.
It can be doubly unique -- okay, ridiculous -- when the vehicle is supposed to be in a realistic situation, like the Paris-Dakar Rally car. A recent example of outside-the-box vehicle use would be Mommy's Best Games' Grapple Buggy, a game that many gamers nearly fall in love with when they hear just the name. In general, a comedic bait-and-switch technique could get some attention, too -- imagine making a Forza-like racing sim where you suddenly go from a tarmac time trial to having to fly a Subaru in an aerial dogfight.
In a Nutshell: Shoot 'em-up design coupled with a medieval swords-and-sorcery aesthetic. You play as four different warriors, one per stage, and you must keep them alive before they join to face the final boss. When a character dies prematurely, they're gone for good, and the game shifts to the next character, in their own stage.
Legacy: Square published King's Knight some time before the first Final Fantasy, when its track record was not so sterling. The game ended up disliked even today, partly due to its difficulty, but also because of its vague setup: the environment can be destroyed by the player's projectiles, and constantly reveal piles of power-ups that become almost overwhelming and smack of uselessness. Coupled with a need to collect a special item for a character as well as keeping them alive, you got a game that failed to be understood in its time and paid for it.
What to Consider: Most action games feature one hero with multiple lives, but King's Knight's approach isn't used too often. Sure, it's a bit harsh, and anything that takes after it probably doesn't need the player to collect a bunch of items and survive to the very end, but it's an interesting way to deal with failure in games. Life goes on, in other words.
And in a broader view, the arcade shoot-em-up style could always use a fresh concept, even if it's an on-foot, medieval affair where you can chip away at mountains with your magical beams.