Essentially, the game you see taking place actually happened ten years earlier. The bodies the police found are from Logan's copycat game where he chose similar victims. Eleanor's fascination with Jigsaw and her creepy engineering skills are a red herring. I thought Logan was too suspicious too soon and it felt cheap. The sudden timeline reveal also felt cheap. It was done better in Saw 2 when the cops realise too late that they aren't watching a live feed. The way the plot works in Jigsaw felt like they weren't sure what they wanted to do and kept rewriting it. Plus they wanted to shock you with "John is still alive?!
But of course he's not and I'm so glad they didn't try to go such a cheap and stupid route.