The background seems unbalanced, in that there are more colors on the right side than the left, and what I am guessing is the floor just seems cut off (but then again I am used to more full portraits by artists such as Alex Grey)and it is more filled in. As for the characters, they are drawn well but seem to be awkwardly posed: I can't tell if they are fighting or embracing. And it looks as if the one kneeling down is missing a part of the right leg due to the clothing.
The two things I would focus on are filling out the rest of the back ground to even it out, and brighten the clothing somewhat, or remove it entirely, as it's quiet dark and dull for such a colorful and trippy background. The background fading is very cool though, with the foreground being more colorful and brighter than the furthest background.