The end of Fez when Continuum plays(when you don't have all the cubes) is probably one of the greatest experiential moments in any medium that I've ever had. Plenty of other moments in the game where the music works perfectly in tandem with the visual and gameplay sides of the game.
When I got there I just shot that cube below me raising me above the wall, grabbed it while I was standing on the wall and shot the cube at the floating one in the center of the platform. I also got all the hint pictures and finished every part of the map (except the ending map block) so I think I found everything except for that pink cube.
As for Connecting the pieces the best hint I can give you is...
As for crits, since he is already very humanoid I would stick with that and change his feet to boots because having toed feet and the suggestion of boots looks a little weird as it is. I'd also say give him some wrinkles on the areas where he is wearing clothing such as his legs, gloves and boots because right now it doesn't seem like he's wearing any even though you've put in some of those details. Once your done with the major forms I'd say add some suggestions of fur and some grain and scratching to the antlers to add a little detail. Look forward to seeing where you take this.