Dude! this is sick! you should take that spider person to the next level. bring that polly count right up! xD digital tutors have some awesome modelling tuts! i think that spider guy would look nuts if he was properly fleshed out. here look at this >>http://www.digitaltutors.com/tutorial/1124-Creating-a-Sci-Fi-Robot-Warrior-in-ZBrush
crazy amount of detail! but you should defiantly look into it! your designs could be taken so much further! keep up the good work man! :)