Lol completely different from my rough draft, but definitely on the right track, and your method looks more direct and less convoluted lol. 
Only a few things:
Regarding the zone 1 side
if (SOCIALTWOCOMPLETE) {
@overlay TALKBUBBLE2 shifts to 388 348 in zone 2 in 0 AND overlay TALKBUBBLE2 opacity 0 AND MAIN moves to layer 2 AND MAIN spot 1.280 164 -46 in zone 1 AND MAIN faces left AND MAIN is think
@zoom reset
} elif (SOCIALTHREECOMPLETE) {
@overlay TALKBUBBLE3 shifts to 388 348 in zone 2 in 0 AND overlay TALKBUBBLE opacity 0
} else {
}
If there’s an if, then an elif, the computer will only pick the first one it sees. It’s best to have two independent "if"s, bubble3 being completed doesn’t depend on bubble2 being completed, the readers can do it in any order.
My edit to the zone 1 side
if (SOCIALTWOCOMPLETE) {
@overlay TALKBUBBLE2 shifts to 388 348 in zone 2 in 0 AND overlay TALKBUBBLE2 opacity 0 AND MAIN moves to layer 2 AND MAIN spot 1.280 164 -46 in zone 1 AND MAIN faces left AND MAIN is think
@zoom reset
} else {
}
if (SOCIALTHREECOMPLETE) {
@overlay TALKBUBBLE3 shifts to 388 348 in zone 2 in 0 AND overlay TALKBUBBLE opacity 0
} else {
}
That should allow the reader to play the game, however, there still needs to be some “check” sequence that’ll let the reader out once all 3 gains have been gained.
With the setup that you have now, you can put a “check” at the end of each bubble’s section, that checks if the other two are finished.
Here's what it would look like at the end of bubble3
} “TALKBUBBLE3” {
#CONTINUE SCRIPT HERE#
gain SOCIALTHREECOMPLETE
if (SOCIALONECOMPLETE){
if (SOCIALTWOCOMPLETE){
goto CONTINUE_STORY
}else{
goto ZONEONESOCIALGAMESTART
}
}else{
goto ZONEONESOCIALGAMESTART
}
}