Hey, you guys helped me once before in this thread, and a couple more games came to mind.
Both games I played about...10 years ago or so, if that helps date them.
First was a upscrolling shooter, I think, in which you were a super powered car of some sort, which machine guns. Graphics were sprite-ish. Anyway, you could upgrade your guns, you could leave oil spills behind your car, all sorts of things. There was a desert level...can't say much more about it.
Second had non-sprite type graphics, was sort of a top down space shooter. The "world" was a massive grid, and on each square of the grid was an open, square-shaped part of space in which you could fly around, mine asteroids for gold or something, clear the area of aliens, and land at bases to upgrade your ship. There were different types of ships, faster/weaker and slower/stronger, different types of laser weapons. Missiles at some point too, I think.
Anyway, I've searched for both for a while, and could never find them. As you can imagine, they are somewhat generic, so if anyone has ideas or names I could look up, I'd appreciate it. Thanks!
Oh also, both of these games were on the computer, both on whatever the Windows OS was at the time.