Did he say this? Any chance you have a link? I'd like to read it.
If he did say it's "not a game script", I wouldn't read too much into it. He likely just means that the script doesn't succumb to the pratfalls a lot of video game scripts do, and feels like a naturally told story. Plus, in a more literal sense, he physically acted out all his scenes as if it were a play or a movie, so, to him, it probably *didn't* seem like a game script.
It's like how I love plays and theatre, but if a movie is particularly wordy or boring, I may say "this is like a play or something!".