The Sega Game Gear already has a ton of great shoot 'em ups, but it could be about to get another later this year, in the form of the Suzuki Plan's promising naval barrage game Battle Marine (as reported by @GGEAR_TARO).
Battle Marine was released on Steam earlier this year in February and was described at the time as a "somewhat retro yet new" experience with plenty of powerful lasers and explosions.
It saw players assuming command of a naval vessel floating above a sea of enemies, with the goal being to achieve high scores, through avoiding projectiles, building up combos by chaining attacks, and collecting various medals that are dropped onscreen.
It was built with a custom SDK called VGS-Zero, which is a virtual game machine "with a fast 16MHz Z80 CPU, old-fashioned VDP (Video Display Processor) and VGS (chip-tuned sound system)" and has since been successfully ported over to the Sega handheld.
It will be released this September on cartridge and will feature an additional secret stage with music from the composer Tadahiro Nitta (who worked on various Microcabin games like Xak, as well as Final Fantasy MSX, and the Dreamcast classic Shenmue).
Here is the trailer for the original Steam release: