[SuchFriendsAreDangerous]

I believe what would be considered the same about these songs is called the "key" or the "scale". they are harmonized together through the notes along the melody that they share in common, though not enough exactly to be the identical song. Further, Jim used the same tempo, and a very similar progression [ie, the succession of notes played either in chord or melody format], the drum beat is nearly identical as well.

my vote:

the tempo/timing/progression/harmony/melody/scale/key/and drum beat are at times identical and others nearly identical enough to be the same song..

once it gets to the drum part to can actually sync the songs up together perfectly and not even notice a difference, they in this way compliment each other, which is what I feel Jim was going for, it sounds like Jim took the base from the Floyd tune, and added upon it the sounds and effects he would have liked to hear with it.