The same difference that there is between sharks-01 and sharks-02, or between esi-01 and esi-07: different code that produces almost the same output. I was puzzled myself about this when I joined the c64intros crew and I was tempted many times to remove these.
I think it's time for us to implement "alternative versions" linked to the main entries, to avoid these apparent duplicates. There is a shitload of intros with graphics or different effects that would be nice to add as alt versions
So what's the major difference between this and Bros-02?