well... I am not sure if I have any critisism to give... I have no idea what these are for, they kinda look like advertisements, and if they are, what i say may be way of in terms of making people want to do what the picture tells them.
of course i would like to help... sooo...
1: Its kinda trippy to see a persons face segmented and rendered individually. I am glad you did it in horozontal rows instead of vertical collums because it preserves some facial symmetry. i don't really have any constructive criticism with this one... oh... and whats in her mouth?
2: I like the spinally text in front of a spirally patterned background. It looks very professional, except the logos have white boxes for the most part, when I think they should all have a dark black box (dark enough to be seen over the shirt) and in some cases color inversion like the Yamaha one. Also, the pupils make this look a bit silly, this could be a comedy movie i guess.. but if its anything other than that i would suggest picking one and altering the other.
3: I love the shadows and blur on the text in this one, but some of the cat toys look like they have been pasted in, and not completely blended. and others look like they blended too much and became so blurry you cant tell what they are anymore. I don;t know if its worth fixing though because that text is beautiful and eye catching. without forcing myself to notice the details on this one I wouldn't have caught it.
4: I dislike decapitated animals and I would never go to this zoo! (but i find the simple style of this will work out for the average person perfectly)
5 I have no idea how you did this one, but it is impressive. the size of the 'T' varying to fit the picture as well as the light color scheme make it look amazing. I dont have any constructive criticism for this one.
6: I am not sure about the text in this one, There are too many repeated characters so the bloody look doesn't fit well in my opinion. especially if you use it on the spine of the book and the front. The scorpion image looks really good, i like how it blends in with the black. i think the image could actually be used more than once, like a small version on the spine and/or on the back cover and flipped horizontally. It looks really good so it may spruce up the blank parts.
Anyways they all must have taken forever, and when it comes down to it, all of them look great, so make sure you don't kill yourself! I always say "when it comes to editing you will never get things done completely, you always work until you have something that's close enough." in other words, you will always find something that you can change up. don't worry about it being perfect. just make sure it does what you need.