#1 I'm actually wondering how you did the first section of tiles you posted.
To me, they look like actual scanned in drawings with pencil then created on a computer. Not that that's a bad thing of course.
#2 As for the current piece. I'm guessing the main character is on the left, yes?
#3 Make it a little bigger to stand out more. It's shading is good, but, well, it's still lacking something that I can't put my finger on.
#4 Also, the bouncing critter. Why does it's tail stay stuck when the rest of it is moving? That should be able to move as well.
Just my thoughts.
#1 for i how i did this, it was actually a 100% done with computer, nothing were scanned, i only the filter from photoshop for to make more sharp before i converse them into 8 colors schemes. but now, i'm using more graphic gale than photoshop for pixel art.
#2 yes, you're right. it's the dino-like that was the main character.
#3 i can't make more bigger or more shorter because of 8x8 and 8x16 rules. so, i prefer to stick on this actual size.
#4 that is because i haven't yet finished it, i did mentionned it few post ago. beside, i changed the monster for a boss that you can see there :

i indeed removed the loop stuff because the new monster is not yet animated. ^^;