Midnight Mysteries: Devil on the Mississippi is a little different from most hidden object/adventure blends that have been coming out. Mainly, that's because it actually leans more towards the adventure side of things, where most games in this style throw hidden object screen after hidden object screen at you and only give you the occasional inventory-based puzzle.
Midnight Mysteries is actually light on the hidden object puzzles, and, unlike others of its type, doesn't give you inventory items from these screens alone. Instead, you will be able to pick up necessary items lying around the story's locations. This, plus the fact that the game offers more than just the standard fare of inventory-based puzzles, really helps to give that adventure-first feel. Devil on the Mississippi has a slew of dialogue-puzzles, though they aren't very complicated, and other, more critical-thinking-based puzzles, some of which are a bear to get through.
The game's story is pretty interesting. The main character is approached by yet another ghost, and this time, he is whisked away to the mid-1800's to help Samuel Clemens, AKA Mark Twain, resolve some last remaining detail of his past. All we really know is that the author's ghost is being pursued by some devil and helping Twain will not only let that soul rest, but also maybe let your character get another quiet evening alone.
Your time on the ghostly riverboat is strange as you will find yourself seeing clues and meeting people from Twain's books. As a result, you aren't sure if this vision you are having has you in a real time and place, or actually sucked into Twain's ghostly imagination.
When you do finally get to the bottom of Twain's turmoil though, you find you need to dig deeper since it appears his troubles are rooted in Twain's beliefs towards who did or did not write the Shakespearean works. The basis of the second half of the game comes from Twain's book, "Is Shakespeare Dead?".