I agree with Pontos. If you can get the heroes to have a bigger impact earlier, the player will "bond" with them more and want to keep around one that has helped them through the beginning stages. I imagine that part of the game could be more RPG-like with skill trees and such for their experience levels.
 "Factory Balls, the Christmas edition")
 "endeavor")
 "Rescue On Cocoa Farm")
 "Vertical Drop Heroes"){kind=logo}
 "Demolition City 2")
 "Picma")
 "BoomsticK")
 "Dead Frontier: Outbreak")
 "Storm the House 3")
 "Castlewars")
 "Crunchball 3000")
 "Bunni: How we first met")
 "The Archerland")
 "Cyber Recession Warrior: Edgar")
 "Learn to Fly")
 "Protector III")
 "Splitter")
 "Spewer")