Z-Axis Exploit : GW Submissions

Guild Wars does not have a true Z-Axis. Characters that are next to each other on the minimap can hit each other normally, even if one is way above the other on a bridge. Warriors can pound on enemies underneath them, will affect enemies on both heights, and you can even body block someone from above or below.
The best trick with this is the necromancer teleportation skills. When you teleport to a location you always show up at the highest point. Teleporting to a corpse below a bridge will put you on top of the bridge! You can't always plan for it, but it can be a real lifesaver.