Hi,
Not a pro composer here but I am into sound design and I listenned.
First off I did not listen with a professionnal audio system so it might be a little bit off.
With my system (headphones) it felt like you definitly need a whole lot more mixing. Especially the drums. I think you need to EQ them a little bit too but maybe that's my headset so you should wait for another opinion.
For example in the second one you have the drum kick (or is it low tom?) which is very weak/lack a lot of "brillance" (for lack of a better word, I'm not english), while you have the HH which is very loud right in front of the face. I don't know if you choose to do it this way but it does seem weird to me.
Also and this one is personnal but I feel you really overdo the pan.
I won't comment on the quality of the music itself because I am not a composer but I liked some of it, my favorite being the third one, although I don't know if it's good for a demo reel because it's repetitive (not overall but each part). But I don't have composer demo reel experience.
Long story short I think you need to work on the drum mixing but wait for some other guy to confirm this or say I'm wrong.