That's strange. I just copy-pasted the .js file and I didn't have any errors at all. Make sure that when you add new questions, the closing bracket always has a comma next to it. (Highlighted in red)
Code:
{
"question" : "Q1",
"choices" : [
"answer"
],
"correct" : "answer",
"explanation" : "explain",
},
{
"question" : "Q1",
"choices" : [
"answer"
],
"correct" : "answer",
"explanation" : "explain",
},
If you don't the game will break/produce errors.