The Pokémon OW's look...not so great. Turtwig's stomach sticks out the same length than it's legs, and it shouldn't be seen. Grotle looks like it's laying down and what's with the bug eyes? Chimchar is un-even and it seems like its head is shifted to the left, and you have to squint very hard to see its eyes, you want to be able to make out the face clearly. Piplup's body span is only 4 or 5 pixels wide, but the head is huge, you want to keep things even, once again.
The trainer is an obvious edit and it looks like he's missing his eyebrows. The beret on the front sprite is to square and you can still see the bill of what once was a hat, the side sprites are decent, probably the best you have, but the top of the hat is to straight. The back sprites are edits of Red, and I don't even know if it's been editted. To hole in the hat shouldn't be there (it's a beret.)
Turtwig - 5/10
Grotle - 3/10
Chimchar - 3/10
Piplup - 1/10
Diamond - 4/10