If you just power through the game and ignore all side content, it's a somewhat short game (maybe 1.5-3 hours), but if you take time to explore all options and try to 100% percent the game (max stats, all outfits, sandbox, achievements, etc), it becomes much longer. I have over 8 hours on the game and just finished everything with chapter 7 (minus the chess grandmaster achievement), and there are at least 13 chapters.