Note: I did not do all of the mod, this was a joint effort of both me and my friend who want to learn how to mod. (although it was my idea :p)
Some of the changes:
Homing rockets
anti-air defenses (as this mod was built around a carpet bombing banshee)
Nuclear missles (still might need to work out some balance issues... heh)
not really much, Its kinda simple as I did not have much time to mod due to lack of getting to use a computer during the week much.
Pictures:
The added zoom on the sniper
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The 4 shot homing rocket launcher (also nuclear)

The AA warthog gun

The carpet bombing (sorry for the bad screen shot, ill do better later)

The nuke (note warthog in distance)

And the flack cannon from needlers

Hmm i guess i use a PPF since i did not rebuild the map...
I hope i did it right, and if so here ya go!
also, please dont be too harsh, i know it is not that great, but still...
PS: copyright wise, just dont be a jerk, mess around with it do what you want but credit would be nice.
EDIT:

Thanks:
My friend Riley for his help, All the people who answered my questions, Jim Raynor for his tut's and everyone else for theirs (too many to remember) and everyone here who proved to me that mac modding is possible!