Game Maker 8. :U
I'm too lazy to learn Flash or C++ or whatever else would be suitable, plus Game Maker cuts down the time spent with coding quite a bit. I have a decent idea of how to implement most features i've planned, without them being... Well, lame.
Also, i kind of forgot to mention that the game may require a tad of multitasking, for those that desire it. I'm thinking that there might be two ways of controlling: Keyboard + mouse and keyboard only. Controlling the ship's movement is always going to be keyboard, but what differs is how you control your weapons. See, you have two primary weapons: Front guns and a turret. The front guns are what you'd expect, and the turret will either be mouse-controlled or auto-tracking, depending on which controlling mode you've selected. The turret is to provide you with an edge against the enemies, which primarily fire in a fixed pattern. The turret is going to have less power than the front guns though, so you'll be needing both to succeed.
Also, with some luck, i might be able to implement a level system. As in, XP level. One can never have too many levels. When you gain a level, you'll get some points that you can invest in various abilities, such as health and damage.
However, the part of the development i look the least forward to is sound and music. While one can acquire decent sound effects for free on the interwebz, i have NO idea where to get music, and i'm not a composer myself. If you know of a good place to get free music legally, please tell me of it. I know games can TECHNICALLY function without music, but it quickly becomes boring.
@DarkJak: Much appreciated. :>