As its name implies, this homebrew is actually a PSP version of the highly popular Sudoku number puzzle, originally created by Howard Garns back in 1979.

Here are the rules:

1. Fill the grid so that the numbers 1 through 9 appear in each row.
2. Fill the grid so that the numbers 1 through 9 appear in each column.
3. Fill the grid so that the numbers 1 through 9 appear in each 3x3 box.
4. A complete Sudoku puzzle contains the numbers 1 through 9 in every row, column, and 3x3 box.

Sudoku Solver/Generator Source-Code from Ohad's blog

Jas Game Engine++ (c) James Hui (a.k.a. Dr.Watson)

Thanks to Dark_AleX, TyRaNiD and the rest of the pspdev team.

The above mentioned names do not endorse me or my work.