there are 9 ghosts in total, not just 3. there are 3 ghosts in each of the 3 rooms. trying to solve the tasks from the achievements adds replayability and more playtime than "just 1 hour". but even if the game was just 1 hour of playtime without any of these further options, "hours of content" shouldn't define the price because you never know how much work is behind making such game.