Instinctive Reaction

Instinctive Reaction is a concept for incredibly hardcore and fast-paced gameplay. Your character will sprint at high speed across a variety of levels automatically, and you have to leap, attack, dodge, walljump, and grab at the right times to make your way safely across. Timing is the key, one mis-aimed press and you'll hurtle into deth. I guess it plays something like a rhythm-action game, but with platforms instead of questionably dressed men. Of course, this on it's own wouldn't be all that hardcore. But, because of the speed you fly through the levels, and the amount of obstacles on the level, you'll need to really keep your concentration to make it through the level. And, some obstacles will move (including enemies). Because I want it to be one of those games that you'll yell at for it's unfairness, but know that really there's nothing unfair about it. It's just very very difficult. If it all went to plan, it would be a game to keep coming back to to try to beat your previous record.
The main character is an elven girl, consistantly composed but obviously fast and powerful. Character reference? See Arya in Eragon (the books, not the "meh" film), or Gardevoir in Pokemon (but obviously more human... well, elvish).

Oh yeah, LEVEL BOSSES. How would they play? Well, I have two ideas at the moment. In one scenario, it plays out something like a normal level, except you have to leap your way towards the fleeing boss and attack when you're close enough. Repeat enough times to kill it. lternatively, you're in a large square room with rounded corners that the elvish lass has no real difficulty sprinting around. You'll be able to make her turn to dodge attacks, and you'll need to find the most effective ways to defeat the boss (so they play out more like puzzles - very unimaginative on-the-fly example: the boss fires missles that home on you. Get enough speed up to get to the other side of the boss, and it's missiles will hit him rather than you).

One more thing. To ease the pain (only slightly), you have a boost bar. It doesn't have much juice, and doesn't recharge, but you can use it once per level to blast through a short section without having to hit any buttons. Against bosses, it grants a short period (about 2 seconds) of invunerability.

So, that's that for this concept. This is one I'd really love to see created, too. Maybe I'll get to make it some day.