Thanks for getting back to let us know,
I read up about the retropie software but the site didn't explain, sufficiently for me, exactly what it was.
The game needs hardware graphics acceleration from somewhere because of the number of objects and for shaders etc.
For that it needs Windows and DirectX9 or suitable emulation.
Usually, these raspberry pi boxes are like a casio calculator with USB ports.
At the moment, I'm still working on Dai-X's quantum blaster and then comes some other stuff before I release 0.84d.
I made the Dai-X junction completely automatic to make it less of a faff to get at.
You just have to hold down the shift key for long enough to get from X-Bomber to Dai-X.
The auto Dai-X junction is finished and it works really well.
The continued work on Dai-X's quantum blaster is coming along well too. The new weapon sprites look good and the two firing modes; combined mode and rapid-fire mode work but need further tweaking.
Dream big and bold and daring.