Progear

Sometime in the past, the people of the country of Parts had found a way to become immortal, but only with elderly nobles. Five of these elders—Ballossum Pench, Gabriel Hammer, Jimchuck Spanner, Olsorro Slasher, and Leonard Drill—obtained immortality, and became known as the Motoruin sages. Eventually, they attempted to take over the Parts kingdom and start a new world order, collapsing the government and destroying parts of the country in the process. As their plans unfold, five children of one of these villages decide to battle the Motoruin using another new invention: the semi-automatic propelling engine, known as "Progear".

Progear is a 2D horizontal scrolling arcade shooter. It's Cave's only side scrolling shmup until Deathsmiles in 2007. The game basically follows the bullet hell style - many bullets to dodge and enemies to kill, plus very big bosses at the end of each level. A player can choose out of five kids (two male pilots and three female gunners), which affects the shooting. The scoring is influenced by a system based on rings/gems, generated when enemies are destroyed. The game's art design is steampunk based.