1- the picture is under exposed, making him dark. He is also blurry from motion.
I don't see the need to have an aperture of f/16 for this. Why the f/16? If its just a "whatever setting", I'd suggest reading up on the triad of exposure and how they work together...shutter, aperture and ISO.
Opening up the aperture to an f/5.6 or so would allow for a faster shutter speed, which would of frozen his action and if you are metering off of him, it would of exposed him a bit better.
But careful in choosing your backgrounds for subjects... he is wearing a dark shirt and the background is bright, so its hard to get a proper exposure on both him and the background.
I'd chose a different background as well as open the aperture
I also don't like the composition. I don't like him being so far left, I'd prefer him on the opposite right side. Same framing idea, just on the other side. Personal taste though.
2- Same as 1 in terms of exposure and freezing motion. Move in closer (or zoom in closer) to get rid of that background playground. I find there is too much foreground ramp as well
3- Same as 2, move in closer and fill your frame with the subject. I really don't like the mug shot style of this picture. Zoom in really really close to get rid of the entire glass and just have the coloured swirls in there.
And avoid the flash if you can, bring in extra lights from other rooms for better lighting, or move everything outside in the shade on a bright sunny day.
So.... read about composition (rule of thirds, angles, golden photography rules), read about exposure (I suggest a book called Understanding Exposure by Bryan Peterson)
Keep shooting!