each time you level you get 15 points to put where you want.
each time you level the exp for your next level will be 200% more than last time
-1-100
-2-300
-3-600
-4-1200
-5-2400
AND SO ON
anything you defeat will give you exp.
the exp you get will be equal to there Reiryoku/20
you also gain 100 Reiryoku each level and 200 health