I rather like the color choices.
However it doesn't look as though you planned the painting with a sketch first, what with the robot not being symmetrical. The upside-down triangle that frames its eye - being off-center - really throws the whole piece off for me.
There are some shadows you could stand to darken, I'm looking particularly at the back of the wheel where it appears to be beneath the robot and facing away from your light source.
I can't quite tell if its night or day. Your sky tells me its night with its moon and horizon, but the colors and shadows on the robot say otherwise.
One more thing: when you're photographing your paintings, try to fill the entire space of the photo with the piece. Leaving un-cropped edges is distracting and really takes away from your composition and impacts the viewer's overall impression of your work.
The one thing that really bothers me about this is that upside-down triangle on the robot's face. Overall though I think its pretty good.
Thanks for that detailed critique. I'm really gonna take that and improve my art further. Just what i needed!
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