They want our money (The way to win is to spend spend spend) They make you desperate to buy stuff and what do you use to get resorses and speed up anything really. So to get into the addiction they start you with 100 fuel and then Drip feed you the fuel so you buy more. It's an outrage!
This game needs updates like: Fall back Hold and Attack tool; 4x speed; Earn crystals option; Not as hard to complete chapter 1 and 2 and Normal attack for Hero