Beat Shenron. Took about an hour, understandable for alpha. Personally I like to see more strategic direction when raising the character. Currently the best result is to evenly raise stats making the character very cookie cutter. Maybe separate the stats into paths for like a speed build or what have you. Up to you ultimately.
Oh and that dog with the squid face on the 2 cost missions could probably be moved to 5 cost since most of the 5 costs are easier that the squid dog.
Finally a quota system for the hero might make things interesting. Like you must at least attempt heroing or fame goes down. Maybe a currency fine from the "hero guild." Just some ideas. I see plenty of potential so keep up the good work.