Probably 80%-90% of 13-2 is its own story. One of the main characters was a side character and largely uninvolved in the original. The other main character is an original character. The enemy is original. The very ending is relevant, but summed up with a little bit extra.
The biggest thing you’re missing out on is the context of random characters from the first game showing up in the second.
Do I need to finish 13 first?
Probably 80%-90% of 13-2 is its own story. One of the main characters was a side character and largely uninvolved in the original. The other main character is an original character. The enemy is original. The very ending is relevant, but summed up with a little bit extra.
The biggest thing you’re missing out on is the context of random characters from the first game showing up in the second.