I'd suggest some kind of limit on grabbing the enemies. It's fun but completely ruins any challange. Maybe a stamina or the squirm loose or the enemies become enraged. Holding a guy and punching him in the face is great but using him as a weapon is too effective right now.
Actually now that I think about it just make enemies kick enemies away and not damage them. Then you still have fun and can use/throw enemies but have to really use weapons to fight.
Also even though it's a demo please implement a level select to at least beaten levels or just all levels. I played for quite a while and want to finish but don't want to have to leave it running.