I don't feel quite right about them, HELP

Try a hair light as well... It looks like the top of his head melts into the background darkness in pics 3 and 5 specifically. #4 would too if the crop wasn't right on top of his hair. Overall decent shots. I like #1 the best though. I think it shows the most personality.

I think there is to much busyness from the shirts. I usually suggest for portraits solid color so not to take away from the subject. For a portfolio of some one like this most of the time they are looking for simple. I would reconsider background colors. There is to much to draw my attention from the face. I think your light is mostly good but vary it some to more dramatic to simple. Always try to stay away from flat light. Look at your photo and see what grabs your attention first. If it is not the subject something is wrong. As one already said a hair light may help in a couple of them. #3 is good for a fashion shot. His expression is great but again I am drawn to the clothes or the background first. I would also crop him to where there is less space behind him and maybe more in front of him. One thing to remember in photography, often less is more. Simple rules most of the time. But all rules are made to be broken at the right time. I hope this helps.

Good job.

Posing is not as natural as it could be...and try a black background. The dude's skin tones just don't hit it off with the backgrounds. Technically and compositionally, it is right on though.

I like 5. get him to do it again but look into the camera with his eyes open, face at a similar angle it is there. Love the lighting in it.