You might want to try referencing the cartoon for some interesting stances for Jerry, in case you haven't already done so. I think his hands could be pulled awway from his body and his stance widened for a more ready look. For the tiles, It looks odd to have the grass pop up only around the crate. The crate could, IMO, use some basic perspective, having two sides visible instead of just the one that's seen now. Like | | | instead of | |. The dirt in the ground could use some desaturation and, if I remember correctly from the cartoons, dirt was generally more towards the yellow/orange spectrum rather than your reddish brown.
Thiggidy-thiggidy-that's all, folks.