XEXEX / Konami / Arcade
Xexex clearly attempts to build on Konami's arcade success with shooters like Gradius and Salamander, but it also seems totally content to just copy gameplay mechanics and ideas from earlier games and overlay it with a layer of flashy, colorful graphics.
Ultimately what sinks the game, though, is that it's just too damn hard. Your ship moves about way too slowly to keep up with the ridiculous amount of fast projectiles flying at you (and the deadly aim of the enemies), the rate of fire on your normal guns is too slow (and can't be held down, you have to keep tapping over and over.) Your secondary weapon is a kind of energy tentacle lash forward when you charge the regular gun and release, but they also "borrowed" this mechanic from an earlier arcade game whose name escapes me at the moment.
All the game ends up really having to offer is an excellent Konami Kukeiha Club soundtrack, although most people probably had to pay a high premium in quarters to hear it since the game happily kills you off so quickly.
* Gameplay Video