Thanks for the input! I totally agree with your points.

The big tree problem is that i really suck at texturing, that tree is like my 5th shot and the only one that i was happy with. my idea was a forest with trees so big that you couldn't see the top, but in the end i didn't even achieved that because they are kinda thin. After  i failed at making the texture on the tree i made some tiles filled with mold to add some detail. I will try to start over and make a decent tree. Here my first mockup (which submitted to PJ) to demonstrate the difference on the normal tree (i didn't post it here because i wanna change some stuff like the tree pallete and the clouds):




The background idea was a parallax scrolling with multiple layers. I admit that it looks like a bunch of stripes and i was kinda lazy, but i thought it would still give a good effect while moving. I'm also willing to change, what do you guys suggest?

Edit: i was with this in mind, that is why they are so straight (http://kauilapele.files.wordpress.com/2012/07/tall_trees_encircle_sunlight_1000_billfrymire.jpg)



As the leaves tileset, at first i had only the first 2 sets of rows, but then some of the back leaves didn't have any good mach with the front ones, so i created the third row to act like a backup, where the front leaves were made specially for each back leaves (on the mockup with the blue sky, i only used the first 2 sets)