Squares can move and capture diagonally forward and straight ahead forward.
There are just 30 levels, which is great! At the moment, I'm stuck on level 18 - the grids are small, but the puzzles get pretty tricky.
Other chess-like puzzles that I've blogged about:
Solitaire Chess - my favorite from this list
Board: Chess Puzzle
Mate in 3? Ok!
Chess Puzzle of the Day
Chess Light - very good
No More Kings