vDOS - A Puzzle Shooter in Progress

Overview
vDOS is a project three years in the making, starting from a simple WIP back in 2006. It has been redesigned from the ground up, every little detail checked. Everything is made by me, all the sprites, music, and puzzles (sounds, however, were not made by me).

vDOS is a puzzle/shooter hybrid. You control a mobile gun turret, with the ability to shoot bullets and bombs to clear obstacles and foes. Your objective is to obtain pieces of a powerful amulet from four worlds. Along the way, you obtain power-ups, which open the way for more complex puzzles. There are ten levels in each world, with a boss battle at the end of each.

Demo
The demo of vDOS is, for the most part, the full game's tutorial level. There are ten stages which will familiarize you with the game mechanics, most of all the control for the turret. There isn't too much of an emphasis on shooting in the demo, but there is in the full game. It is simply to get a feel for how the game works.

Download Demo

And comments/criticism is appreciated.

Looking nice, but I think that the ship should look different