I admit, I didn't know what was going on half the time(even after reading the instructions); but you know what, that is okay because I was still able to play. I also still found myself having frantic fun at times. I agree with the others, it needs medals or some achievement system to create re-playability and give motivation. Also, the game needs to get harder over time. I felt like the difficulty barely changed over time. Also, I didn't feel like playing the game for too long because of that and because nothing much changed besides upgrading which only made the game easier.
Overall Opinion: Icy Fishes is a game which can be a lot of fun even if you have no clue what is going on, but it is far too easy.