There are some unlockable items hidden in the in-game shop that become unlocked by finishing the game's story mode to the end (this includes defeating Dr. Wily). Once you have achieved this the hidden items in the shop will become available to buy at a price of three thousand Bolts.

Awakening Chip (Infinite): Infinite Weapon Energy for completing the game.
Cooling System (Infinite): Infinite Double Gear Time for completing the game.