From Steambase:

A revamped version of Tales Gear, originally released in 2007, featuring high-resolution support, new systems, and rearranged background music. A full-fledged 2.5D vertical-scrolling shooter characterized by the Tail Pod, an optional weapon that combines offense and defense.

For more information on the original 2007 version see this article. The game itself is no longer legitimately available anywhere, so this HD re-release is good news!