This is bullcrap, basically every feature is faulty somehow. You want to upgrade your units? Great, now you will have to pay more in order to recruit them (12->24->36 and so on). The enemy does not seem to have this problem - he sends units at the same frequency throughout the whole game.
How the hell am I supposed to play when I can't afford units? Even if the guard tower kills a few enemy waves my won troops still tend to get powned by pikemen or archers. Screw this.
The AI is cheating with their use of boost. I think it should be fixed, at least that it is not obvious as the first racer using up 3 gauges of nitro without the means to recharge it...
You need to pass wave 17 to get the hard badge. My setup was obvious: 3 ninjas and a cat. Level 18 is crazy though, you get to fight 4 dino-rider bosses at once. Not to mention ordinary enemies. Kudos to anyone who manages to beat that one. I was just praying to pass the 30k points mark when I died :)
Not even close to Motherload, but still fun. Crafting system could be tweaked in a way that doesn't require the player to create every item one at a time when aiming to craft something sophisticated. 1-click craft would be a real convenience, and a time-saver.
Insanely frustrating, every time I saw the checkpoint I was hoping this nightmare would end. Unfortunately, it went on and on for what seem like forever. The only thing that kept me playing were, quite obviously, the points.
You'd have to ask them.