In Milestone 1, Powerups were gained by hitting special blocks. The powerup block released, when hit by SmallTux, a sliding egg which made Tux big if he could catch it. The egg acted similar to a snowball, falling off edges and returning on hitting a wall. It did not rebound of badguys, however, but went past them. When the powerup block was hit by BigTux, a fireflower grew from the top of the block which tinged Tux a red colour and let him shoot fireballs which killed all enemies bar flames and stalactites on touch. In version 0.3.0, the FireTux look was redone, making him no longer red but with a little fireman's hat. The more Fireflowers you got, the more rapidly you could shoot fireballs. However, if you backflipped, the hat fell off. The fireballs would not kill flames, stalactites, or will-o-wisps, and Igels had to be hit in the head. In 0.3.1, you no longer lost the hat if you backflipped, but otherwise it was the same. In the SuperTux Meeting 18. August 2007 page, the first item is:
Powers revisited
SuperTux will be losing the ice/fire flower soon, as this is considered a bit too powerful and makes the game a bit boring. Instead, there will be several new environmental items and enemies that will allow SuperTux to use powers. See “throwing snowballs” in environments section as well as “Ice Dragon” and “Sand Shoe Monster” in enemies section for examples.
So powerups are basically down the drain, although there will be things to replace them. See the SuperTux meeting page for more information.