Game mechanics and controls: your initial ability is possessing objects and manipulating them in a limited fashion. You also have limited range, so several times, to cross a room, you have to mess around with objects to create a path. This takes care of the puzzle portion of the game and at least to me, it actually seemed more logical than most adventure games (I love Ace Attorney, but sometimes the puzzle solutions made no sense at all, I did not find an instance on Ghost Trick that made me feel that way). You also can travel over the phone (the equivalent of long range transportation in this game and on some chapters, a decision point as well - "Should I stay or should I go?") and the most important one, story wise: when you get in touch with a recently deceased person, you can travel back in time, to 4 min before their death, and change their fate by manipulating objects in the past. It's a limited set of abilities but the game developers use it in very creative ways. At a later point on the game, another ghost is introduced with the ability to swap similar objects and you tag-team with it on several chapters to solve puzzles. The DS touch screen and stylus are a great fit to control the game and you can rewind time an unlimited amount of times, allowing you unlimited chances for trial and error.
Characters, art style, animation, etc...: the game is full of interesting characters, like the dancing detective or the singing fried chicken restaurant chef, my favorite being Missile the dog (yep, a dog is one of the main characters). Even minor players, like generic guard A have lines delivered with personality and actually makes you wonder what is their background (Panic Dancing Prison Guard comes to mind). The art style is very unique, all angles and strong colors, which I really enjoyed. The game looks great in motion, by the way, the first time I saw the Dancing Detective, I was surprised at how fluid the animation was. Music is very good, just like in Ace Attorney, it fits the mood of the moment and builds up the pace when things are getting serious. Even the save game melody reminds me of Ace Attorney :)
Final thoughts: Ghost Trick is a very good adventure game and any fan of the genre should give it a try. It has a great story with great characters delivered in a very unique package. At this moment it seems my review is the first one (almost 1 week after the game released), which makes me a little sad that the game is not selling well. I really hope that, like Ace Attorney, this game is slowly discovered by adventure game fans and builds up sales overtime.