Gameplay revolves around collecting, software upgrading, equipment swapping, and battling robotic characters in a similar manner to the Pokémon game series. To power up the Robopon, the player could add software and parts to them. Parts had varying amounts of space to store software and determined what sort of attacks the Robopon could use. For example, a Robopon could have an "Armgun" or a "Punch" part, and this software adds certain elements to the attacks. Furthermore, software could be added onto other parts, creating more powerful additions. For example, by equipping a "Thunder" software to a "Punch" part, the Robopon would be able to use "Thunderpunch". Software could also be mixed together to create special attacks - by mixing "Fire" and "Thunder" software, the Robopon would have the special move "Zapp!!". This software could also be removed. If you did so, the attack abilities it gave the Robopon would be removed as well. Because only Sun was released in the USA, not all of the original 153 Robopon were available because the others were located on the Star Version that was never produced in the US. Robopon cartridges have an Infrared panel on their top edge that allows them to trade information using waves much like a TV or VCR remote, allowing the cartridge to react to different objects. For example, pointing a remote control at the cartridges and pressing a button might boost the Robopon's stats, or open a chest within the games. This feature was called the "GB Kiss". The game included over 150 different Robopon to use, with the first 2 releases and then over 168, with the release of Moon version, though some had to be upgraded, similar to Pokémon's evolution stages. The Robopon were classified as either Arm, Move, or Boot. Arm tended to have high offense, Move were fast, and Boot had the highest stats overall. Boot Robopon could not have their parts or software changed. Source: Wikipedia, "Robopon Sun and Star Versions", available under the CC-BY-SA License.