Obstacles are a way to slow down attackers while towers and troops do more damage. They can only be placed on the pathway itself. They work best in combination with towers.
There are two types of blockages, the Barricade and the Blockade. The barricade is basically a cheaper alternative to the blockade. Both stop attackers (except for werewolves) from advancing but allow defending troops to move over them. They work best in front of towers to slow people down.
Currently, the only trap in the game is the spike trap. This will deal damage to every attacking unit that stands on it. It can be attacked by some troops, while others will ignore it.