Einhander - Playstation
http://en.wikipedia.org/wiki/Einh%C3%A4nder
Released by Square in 1998 in the US for the original Sony Playstation. Einhander is a 2.5D scrolling space shooter with a good sound-track and a good variation on the standard space shooter gameplay. Einhander meaning single-handed in reference to a weapon such as a sword give the play the option to mount different kind of weapons onto an arm outside of your spaceship which can be placed at the top or bottom of the ship. There are only seven levels in the game but do not be fooled as most are very long and include atleast one sub-boss.
The story line takes place within a fictional future where the Earth and the Moon are at war. Your ship is part of the Moon's forces sent to collect weapons and reconnaissance.
Einhander soundtrack on Youtube: http://www.youtube.com/view_play_list?p=F02CB6DF89FA5F30&search_query=einhander+soundtrack