After a week digging I thought I would post. I disassembled stargate and made some of the improvements from the Defender II hack that was done years ago. I'm also trying to do a number of other things. I'm fairly confident I've isolated a handful of portions of the code doing certain things (particularly scoring, graphics are not that hard). What I am trying to find now are two things that I am falling flat on: 1) I am trying to find the routine (supposing it is timer based) that uses multiple graphics to rotate for the enemies. There are enemies that have 3 graphics each and seem to rotate through on a strict timer interval 2) I am trying to figure out where the mountains are generated to start playing with that as well. I thought these would be a predetermined set of "graphics too" but I think I am wrong. Putting up the set of assemblies just in case someone can offer some assistance.