Xpower-ups
Whenever you kill an enemy in a rapid succession, the number to the right of the health bar increases by one up to 10. This represents what points you receive for killing an enemy, multiplied by the number displayed. This is useful in certain missions where a high score is required to earn the grade.
Mow Grass
Where there are grass, flowers, mushrooms, other foliage, objects other than crates and barrels, and certain decorative objects, you can cut them down to earn a few extra points towards your main score. This is useful in the certain levels that require a high score to earn the grade.
Various Codes
While playing, press START and enter any of these codes: