Castlevania:COTM or Megaman Zero

[Mr.Nobody]

Since I have already picked up Golden Sun(MY dad was nice enough to chip in the extra ten(Too bad I can't play my GBA till Tuesday).

I just came into another 34.00 dollars. SO should ?I buy

Castlevania Circle of the Moon or

Megaman Zero.

Castlevania might be good cause it last long.

While Megaman is very diffucult and will also last long.

Please respond as soon as possible.