Oh man, this was adorable, and very good.
I like the graphics, they look very cute and well made, and the piano music goes along with them very well too. The creepy music in the Accumulus stages is also pretty great, setting a tense atmosphere when needed.
The gameplay is a complex and interesting puzzle, where you have to step on tiles in the right order to get to the exit eliminating as many tiles as possible (and without blocking your own passage), with some extra elements adding more variation, such as indestructible tiles, cooperation between two characters, special tiles that only one character can step on, orbs that give the characters special movement powers and other stuff.
In the first chapter, the first stages are easy as pie, and the final ones are rather intrincate and provide a pretty complex challenge. In the second chapter it's more or less the same difficulty curve, with the first few stages being pretty easy, getting us used to Isabelle's Orb power, and the next few getting us used to cooperation between Isabelle and Ben, and the rest making for complex puzzles that combine these aspects, creating some quite impressive, and occasionally extremely difficult, brain crackers. The third chapter, on the other hand, begins pretty hard, ends pretty hard, but has a few easy stages between level 69-ish and 74. I actually had to check the walkthrough hints for levels 57 and 75, and struggled to solve the others by myself. All things considered, the challenge curve of the game is nearly perfect.
There's a collection of extra puzzles that I haven't yet tried (in which Ben and Isabelle even wear formal attire!), and a very flexible stage editor, both of which add quite a bit of replay value to the game. I now have to try the extra stages first, and then play some user made content.
One thing that annoyed me a little bit is how I had to click "OK" to confirm a restart after pressing "R", which broke the flow of the game big time. Also, why are there no Newgrounds medals in this game? This is such a hard one I think we deserved some :(
The story is romantic, emotional, and there's that heart warming spark about it. It's about this guy, Ben, and this girl, Isabelle, who were once lovers but both died in a car accident, and they meet in the afterlife with Ben's old dog, Marley. I started the game not liking the characters so much, but then the way the story goes makes things change, since facts about the characters' lives and emotions are unveiled, and you start getting attached to them. There are creepy moments too, especially that black cloud "Accumulus", but overall it's pretty heart warming. The ending left me speechless, for it was sweet on one hand, and slightly bitter on the other. Some dialogs were adorable and funny though, especially when the dog starts talking about dog treats, which gives a bit of comic relief to an otherwise emotional story.
Overall, very fun, hard and sweet game, with a great story and nice gameplay. I like how this game gets to be pretty hard, but has a completely legitimate reason to be hard (that is, the puzzles are actually hard, it's not any design flaw that makes them hard).