Beat on normal. At first I was unimpressed with this game. I tried out the controls in the first level and froze an enemy with the missile type weapon. I then tried to kill that enemy, which was immune to damage while frozen. Then I waited to see if the freezing would wear off; it did not. Hum that is kind of interesting I guess. Then I accidentally crashed into the frozen enemy and took it over. My impression of the game went way up! This is a really cool mechanic and I found the entire concept of using enemies essentially as your hp as you move from enemy to enemy quite interesting. I enjoyed the variety of controllable enemies and found them all useful in their own ways. I disliked the long sequences of nothing happening; there was no point to include those in the game. The final boss was also disappointing easy; I was able to cheese an easy victory by flying right up into the face of the boss where the enemy projectiles could not reach.