I played the demo and I gotta say I love it already. Robotron is one of my fave retro games so I looked forward to playing your remake and so far it looks good. Few issues though, the framerate is very inconsistent due to the amount of objects on screen at a time but since the game speed is actually tied into the framerate it causes problems, this needs addressing (Sorry to patronise if you already had this planned). I think the biggest frame killer is the use of Alpha Blending. DirectDraw and DelphiX especially are notoriously slow at Alpha Blending so I think if you drop the alpha blending it will help a great deal. I was getting just 39fps on a 2.8Ghz with GeforceFX 5800 and 1Gb of RAM. This won't be so much of an issue if you have the game speed independant of the framerate but it still needs sorting. I know it's early days but problems like this need sorting as early as possible so you know it won't be unplayable when you reach the higher levels with more enemies on screen. Good luck and despite what I just said, I really do love it so far.