From GameBrew - a wiki dedicated to Video Game Homebrew.
Puzzle game of hacking a timer. Player can edit the margin of error among other things.
Stop getting a marker as close to the number that are asked.
In order to increase difficulty, player can change the margin of error down to 0.
Player could hide the number and the ability to hide the marker which tells how much was missed or left to the target, and the number of attempts.
Stylus - full control
Up/Down - change margin of error
A - start/stop the counter
R - hide and attempts to reach target numbers
L - Hide counter
Tested on: FlashCard DSTT / TTDS with Firmware 1.17a12