Is the guy just being friendly or is he still interested?

[HauteCocoa]

I am a 21 y.o. college junior and last fall I transferred to a new school and met this guy who works in my dorm building. When we first met, I was studying in out lounge laundry room while I washed clothes. He continued to initiate a conversation with me for long time, (which he does even more now if he knows I'm there). I became good friends with a girl who is his coworker. She said he has VIP access to strip clubs and is used to girls being all over him so he waits for girls to come to him. I was interested until she said THAT. He urged me to go to some shows he was going to in the area last winter, but never explicitly said we should go together, so I ignored it. At the end of school, I got a nose stud and he pretended to like it when he saw me, but later he sent me an IM saying 'nose piercings are kind of a deal-breaker for me'. Since I never asked for his opinion anyway, I shot back with 'I guess we're even because smoking is kind of a deal-breaker for me' (he smokes), and he thought that was funny. There's no 'deal-breaker' if you were never planning on making a deal in the first place- and I have never flirted with him so he couldn't have thought it was coming from MY end- right?! We were both in relationships this spring and didn't see each other but now we're both single and he is constantly complimenting me. Once I complimented him via an IM and he promptly said he was coming to talk to me in the lounge. He is still an RA (on MY floor this time) and he's started telling me how these crazy skanks in our building are throwing themselves at him, and said something about how he 'stopped being so negative'- trying to make himself look better.
The guy seems decent, but I can't totally read him and am not clear of his intentions. I know for a fact that he was definitely interested last year, (due to something he once said when we were chatting that you DO NOT say to 'friends'). But, I wonder if he's still interested in 'something'. Problem is, I don't know what that 'something' is! I know my interest was never clear but I also may be reading too much into it now. Should I just forget it all and keep him as a friend unless he makes more of an overt effort? Or is he playing games? I don't know whether to flirt with him or 'friend-zone' him! Besides, I do not throw myself at and relentlessly flirt with men, I'd rather them do the chasing since that has usually worked better for me. He is 25 and will graduate next semester unless he gets deployed by the Army again, so I'm guessing that if he's interested enough he will make an effort since he's leaving in May!