Great movie but far too late to be a prequel! The lead characters are 20 years too old and they look it! Although not as gore filled as the others, I really liked this movie, especially because it gives John's backstory. I was completely lost at first as I didn't realize that the events in this movie takes place between Saw 1 & Saw 2 so after watching this movie, I went back and watched Saw 1, then this movie then Saw 2 and it made perfect sense so I definitely recommend you watch Saw 1 FIRST then Saw X then Saw 2 to fully understand Saw X.
Again, it was a good movie but...
Because it's a prequel, that would put John Kramer and Amanda 20 years younger. However, because this movie was made 20 years too late, John & Amanda clearly look wayyy too old and bad at that. John looks his true 80 and throwing a wig on a 50 or 60 year old woman doesn't make her 20! It was a huge distraction but aside from this, the movie was good! I just wish they'd made the prequel earlier like 15 years ago!