you guys are funny i mean with just the standard 30 energy it will take you awhile to run out for example the first quest gives you 4 exp per completion and only takes 1 energy so 30x4=120 exp so you need 5 extra exp each level up that gets you (i think) to level 20 a pretty good level to get to without taking a break and if you get it to the 2nd star you get even more exp (5) so a few more levels personally i give this a 5/5 and the energy system isn't that big of a deal in my opinion.
@Raamon you did level 19 wrong if you looked closely at the ball you put the green and black stripes to where you only see 3 when your suppose to have 4 stripes of green and black
to get the slayer medal (100k DMG) lets just say give matt alot of bacon and samuri armor and helm fully upgraded and soul eater fully upgraded if done right you'll be a god XD oh and you'll need to "rebirth" a couple of times with weapons lvls and lvl cap off
lol i got an awesome defence 17 sun gods whole bunch of moab maulers some radars and 4 monkey pirates and 6 banana factory and im on round 93 so far never got a single bloon threw