The original Pokemon titles on Game Boy had some issues with balancing, particularly in their first iterations Red and Green. Psychic-type Pokemon like Alakazam were a nuisance given the typings meant to have an advantage weren't well thought-out. Many Generation 1 Bug-type Pokemon were weak, and the only Ghost-types were the Gengar line — whose half Poison-typing made Psychic moves super effective. One of the solutions to this problem in Generation 2 was the introduction of Dark-types.