An early demo version of the game offered things that did not make it into the final version. For starters there were new types of coins that appeared after destruction of the rocks: C and M. The latter was a substitute for the supply ship that in the final game delivers the missile weapons. There was also a huge difference in a tunnel level section. Its shape was triangular and as such, it can not be seen in the final version of the game. During the flight there are also "shield" coins that can be collected. It hints at the idea that the creators of the game were planning to refill the shield's energy that can be depleted by collisions. Unfortunately nothing like this is possible in the final game.