The game has great mechanics, art, and style, but there are a few things that really bug me. I don't like the fact that the missions or quests that come up usually only apply when they are on the board. For example, I have collected over 3000 cans of fuel and a mission that came up wanted to me to collect 300 more. Why couldn't everything get unlocked as I complete these instead of only allowing to me to unlock them three at a time? I ended up beating the last episode with the gatling gun and had to go back to unlock everything else, which was just plain annoying when I completed many of the tasks 10 times over. You also didn't allow the player to view all of the quests to see what was going to come next.
Another thing that bugged me when the availability of some abilities. The armored shirt was unlocked in the upper thirties, by which time I could already destroy the first boss within a moments of facing it. It would have been useful had it been available sooner. Other examples are the force field, ion strike, and airplane.
Lastly, trying to do the survival mode is frustrating. With all of the movement on screen, it can cause the game to lag. The large amount of coins and items also crowd the screen, making it hard to tell what is coming next, usually leading me to lose.
Unless I'm missing something with this game which would alleviate these problems, I do believe these problems should be taken care of, especially the quest problem that i mentioned.