It will be hard to get the game running well on 12 year old hardware but directX9 is possible. In a matter of fact you can force directX9 right now. Create a shortcut to the exe, right click and go to proerties then add "-force-d3d9" (without quotations) to the end of target. You can alternativly also force OpenGL, you can use the switch "-force-opengl" (again without quotation marks) for that one.
There's still plenty of optimizations I can do and I'll do my best to get the game running faster. If you'd like to help make it easier to understand how the game performs on other machines, I just made this Google Form that I will be putting on the original post.