I felt like critiquing this picture because you put a lot of work into this.I will say the good stuff and the stuff you can work on for next time.You have come along a long way from your first picture and this one which is a big achievement on its own.This background is one of the most detailed backgrounds I have ever seen you make.The river looks magnificent where you made the waves at the end of the waterfall and the dark to light colors as it comes closer to view.The tree and the cliff where the umbreon are is also very detailed.Plus the clouds and moon look very realistic for this picture.The glow and details on the umbreon is good and the shading you did on them gives them a slick, umbreon look to them.
Things I would work on for next time is the trees in the background should be alot taller, even if they are a distance from the trees they are still small from the angle this picture is aiming at.Though your background has surpassed many backgrounds you have done before there is a lot more things to improve on it which will take hard work and maybe checking out tutorials.The background is good but it could be even more realistic than it is now.Also the characters should stick out since they are the focal point of the picture.Overall I was impressed by this piece and expect to see some greater pieces to come!