QUOTE(yaustar @ Sep 24 2007, 02:45 PM)

I sat on the idea for a while and I be willing to take it up if you flesh out the design.
That's my day job

QUOTE
What would make it fun and keep the player replaying the game? Where is the challenge/skill aspect? Reaction? Memorisation? What would keep the player playing once a level/image has been completed?
Initially the fun and challenge would be the same as any reflex/music game, with the added appeal of "making" a picture (a la Picross). Skills are reaction, movement and anticipation, with memory becoming important upon repeated attempts. The challenge is to achieve a 75%+ accuracy rating to unlock the next level. Levels would begin relatively simple and raise in challenge/complexity to give the player a sense of conquest. Later levels could introduce new elements, such as a bonus star which, if collected, raises accuracy by 5%, or enemies you have to avoid that try to screw up your picture. There can also be solid walls which litter the play area (Tron-like) and form part of the picture when complete.
Elements to improve:
* The "enemy" sprite could start flashing a second before making a change of direction.
* Regularly-positioned "Gates" which indicate the correct position you should be at, so if you get far off track you can just head for the next Gate and continue from there.
* Award medals for 90%+ accuracy in a level. 10 medals unlocks an ultra-hard batch of levels.
* (tricky to implement) If able to calculate a running accuracy count, a dynamic music system could be introduced, where the music track becomes more distorted (pitch, tempo) as your accuracy lowers.
* An added layer of difficulty (a separate mode) could be introduced by changing the color of the enemy's "trail" on the fly, which the player also has to match (using 4 face buttons if controlling by D-pad/analogue, or the 4 D-pad directions if controlling by stylus).
The probable inclusion of WiFi on the new handheld also opens up the possibility of multiplayer, where both players compete for higher accuracy on an unlocked level, or even a turnabout "follow the leader" mode. Also an online leaderboard, and sharing of user-created levels.