Progear is a steampunk-themed horizontally scrolling bullet hell game where players assume the role of children controlling a plane equipped with the titular propelling engine through five stages in order to overthrow the Metoruin sages and their new world order. It was CAVE's only horizontal-scrolling shooter until Deathsmiles in 2007. Progear proved to be popular in arcades among Japanese players and garnered positive reception from critics since its inclusion on the Capcom Home Arcade system, with praise given to the anime-style steampunk visuals, gameplay and accessibility, though the music was criticized. Though first released in arcades, the game was later ported to mobile phone platforms, each one featuring various changes compared to the original version and has since been re-released as part of the Capcom Home Arcade plug and play game system. Initially envisioned as a vertical-scrolling shooter and intended to be their last game, Progear was created by CAVE as a collaboration with Capcom and served as their first horizontal-scrolling shooter title, with bullet dodging and enemy destruction being the main focus while adapting the company's shoot 'em up gameplay style in a horizontal format but faced a problematic development cycle before its launch to the market. It was the sixth shoot 'em up game from CAVE, their first horizontally oriented shooter, and their eighth video game overall. Set in the fictional country of Parts, players assume the role of children controlling a plane equipped with the titular propelling engine to overthrow the Metoruin sages and their new world order. Progear is a 2001 horizontally scrolling bullet hell arcade video game developed by CAVE and published by Capcom for the CP System II board.