Devastator is a platform run and gun game for Sega CD that incorporates shoot 'em up elements. The narrative is intertwined with a mini-anime series, revolving around a man named Ryo who steps into an alternate dimension during a machine test at his new workplace, Yaesu. He is saved from grotesque creatures, Devastators, by mecha pilots and embarks on a mission to prevent a disastrous dimensional interconnection.
Gameplay includes controlling a mech, equipped with a chained sickle and one of three long-range weapons, through various levels. The goal is to defeat bosses at each level end, with gameplay shifting between platforming and horizontally scrolling shoot 'em ups. Weapon upgrades are achieved by collecting items dropped by vanquished enemies; similar to Turrican games. Holding multiple long-range weapons is not viable as obtaining a new one removes the existing. A single standard upgrade item exists which can be cycled through by firing at the power-up.
The game's story is based on a mini-anime series, with extracts from the anime being used for cutscenes between the levels. The story centers on a man named Ryo, who begins working for a company called Yaesu as a replacement for his friend Masato. During a test ride with a new machine, however, he is somehow thrown into another dimension. After being rescued there by a group of mecha pilots from vile creatures named Devastators, he learns that nefarious people are working on a connection between that and his own dimension, and sets out to stop them.
Devastator is a run & gun-style platformer with shoot-'em-up segments. The player controls a humanoid mech with a mid-range weapon, which can be described as a sickle on a chain, and one of three different long-range weapons. The goal in each level is simply to reach the end and defeat a boss. Most of levels consist of platforming, but sometimes the gameplay switches to a horizontally scrolling shoot-'em-up. Weapons can be upgraded by collecting items left by defeated enemies, similar to the Turrican games, but the protagonist may only have one long-range weapon; picking up another replaces the old one. There is only one type of standard upgrade item. To select a weapon, the player has to shoot the power-up until it shows the correct symbol.