1. Visual polish
  * multiple square tiles to add variation
2. Sound effects
  * when a unit is killed
  * if possible, a small bit of background music
3. Gameplay additions:
  * powerups: change movement type, remove pawn's attack and movement restrictions
  * new units
  * choose difference board sizes
4. Further visual polish
  * animate the piece making the attack, and returning to it's spot

Bugs of note:

 * [low] the possible move squares don't change if you increase speed via the debug menu. work around: deselect and reselect the piece