This fanart of Mewtwo reminds me so much of Mother (Earthbound Zero) Which was probably unintended, It reminds me of the final boss of it That doesn't matter does it? Well anyway, The shading is really REALLY good and the detail, oh man the detail. I like how you really put the emotion into Mewtwo's Face. The feeling of sadness and loneliness. I don't know much about Pokemon. But that doesn't stop me from seeing the fact that it has quite the fanbase filled with fanart that pleases the eye. And this, my friend, is definitely one of the best pieces of fanart of any game I have seen. Kudos to you, my friend.
Ever since I first saw his movie, Mewtwo's story has captivated me with his tragic past and the dark path he forged in life. In particular, the story of Amber and Mewtwo has always touched my heart in so many ways, and the artist has captures the innocent early days of everyone's favorite Genetic Pokémon. The colors and shading are superb, the effects are incredibly realistic, and the artist manages to stay true to the original art style while also giving it their own personal touch to it. I commend the artist on their work, and wish for future artists to follow this marvelous example.
I don't have a premium-account, but I want to write more than a normal comment since you requested critique.
I think you draw mewtow's anatomy very well. The shading is also good, although I think that the darker violett in the middle of the end of his tail should be at the lower part, if the light comes from above. The glas looks good. The bubbles could be more white and rounder.
Did you use gouache/aquarelle for the blue and black part? It seems like you painted around mewtwo's / the glasse's outlines a "second outline", while you painted the rest horizontally. It would look better, if you blend in these two parts (either using more color/less water or carefully painting horizontally over the "second outline" again).