Artistic, intelligent and enchanting above all.
To those who have not played this game, I encourage you to do so before reading beyond this overwritten paragraph. The ultimate purpose of this review is not so much directed towards persuading potential players, because the game itself makes a fine speech in that regard. Rather, I'll be constructively critiquing the artist himself, and I won't withhold any of the details that may otherwise obstruct the full experience of discovering this game's secrets by yourself.
Now, to the artist and those of you who have the unnatural patience for wordwalls...I recognized the title immediately and became a leap happier in that moment. Of what little I remember of William and Sly, I do know I enjoyed it. While this game did not meet my initial expectations based on those weak memories, it greatly surpassed them in unexpected ways.
Having said that, throughout the game, I was pleased to find details that preceded intuition, a quality in games I strongly admire but seldom find. Some examples: noticing platforms set high aloft Sly's jumping peak, I thought, "I'm sure there's some sort of ability to get up there." That set a potential goal for me, so I was constantly on the lookout for something that hinted towards that ability. When I discovered the first of your adorable interpretation of pixies, I suspected them for their habit of hopping about Sly, even in mid-air.
I wondered what reward awaited from unearthing the Ohnem runes, and upon completing that, I thought, "Oh, yeah! I think these were in the first game." Needless to say, I found their return a terrific convenience, especially when discovering an Ahmni a minutes' trek across the map. Coincidentally, around my first dozen mushrooms, I wondered, "It would be nice if there might be some sort of item or ability that shows me where things are." I expected this device to reveal secrets via icons on the map, but I was rewarded rather with something that didn't ruin the theme of exploration that serves so obviously as the foundation for this game. I became all the more delighted that for those maybe seeking a greater challenge, this option was just that--optional! Perhaps that could have made for another achievement? That is, discovering all the items without the Ahmni Sight.
I recall vaguely my experience with William and Sly in what seems like some odd years ago, yet in playing this sequel, I found myself thinking, "You know, I seem to remember there were some sort of monsters in the original game." I can honestly admit that I began dreading their potential appearance, and I am happy they did not return after all, because I think they may have drastically affected the fluency of exploration in this game.
Now, my initial reaction to the updated art direction was, "Whoa! What happened here?" I suppose that was a neutral thought to start, but as the visuals unfolded while I progressed, I fell in love with the parallax. I can only say that you have nearly fulfilled a dream I have long sought after, and in fact thought I would witness only once I attempted it myself. "Nearly" only in that the parallax succeeded in filling a bit of the visual void left by the inanimate environment. I would imagine the air in those mountains is stagnant, but for signs I discovered that suggested otherwise. Incidentally, the ambience expressed the environment well--I especially appreciated the hootings of owls, which are my favorite kind of aerial predator, and the gentle music complemented the calm mood. Yet, subtle sounds with accompanying visuals could have been a subtle way to hint at the location of an Ahmni while aiding in the variety of progressing the mountain, such as a babbling brook for the water Ahmni, a cracking fire or bubbling magma for the fire Ahmni, etc.
The journal was an excellent motivator, since it expanded the depth of the setting while sharing a story. It seemed to join every element in the game together and connect me to it, too. After years of searching, I have finally experienced something I can describe as enchanting. I only wish I had more room to type.
Oh, and thank you.