The minimum system specifications depend on how effective my final code will be but it'll run on most systems when it's finished unless you're having a real old rig. The Blitzmax 3D module MiniB3D doesn't support shaders and uses only OpenGL 1.x so the main calculations are made by the CPU but I'll try to keep the GPU busy, too. Minimum screen resolution will be 1280x800 (16:10), with a scaling view and a scaling GUI.
And with more experience in using the OpenB3D framework instead of the outdated miniB3D I could even improve performance with GLSL shaders and other useful functions, but this depends on how effective my shader experiments will be finally.
Inputs are Mouse and Keyboard only, Sound and Music are in Stereo. Nothing special so far for an Indie game. I'm thinking about localization from the beginning, object oriented programming for sure, releasing the well documented source code when it's finished. So if anybody has suggestions or improvements he could play around with the source.
Not quite Open Source, but opened source.