Where hazards exist to hurt the PCs, blocks prevent them from doing things they want to do. Blocks can cause stress, though they don’t always. The chief differences between blocks and hazards is that blocks don’t take actions and are more difficult to remove. Blocks provide passive opposition in certain circumstances, and can threaten or cause harm if not heeded.

Like hazards, blocks have a name and a skill rating, and the name is both a skill and an aspect. Unlike hazards, a block’s skill rating shouldn’t be much higher than one step above the PCs’ highest skill rating; otherwise, things can get frustrating quickly. A block can have a Weapon rating as high as 4, but it doesn’t need to have one.

Blocks only come into play under specific circumstances. A Vat of Acid only matters when someone tries to cross it or gets thrown into it. A Chain Link Fence only affects someone who tries to get past it. The Animate Statue only prevents entry into a specific room.

Blocks don’t attack and don’t have a turn in the initiative order. Instead, whenever a block would interfere with someone’s action, they’ll have to roll against the block’s rating as a set difficulty. If the block can’t cause harm, it simply prevents the PC from taking the action they wanted to. If it can cause harm and the PC fails to overcome the block, the PC takes a hit equal to the amount by which they missed the target.

Characters may try to force someone into a block as an attack. If you do this, you’ll roll to attack as normal, but add a Weapon rating equal to half the block’s Weapon rating (rounded down, minimum 1).

Finally, some blocks can be used as cover or as armor. This is situational—for some blocks, it simply won’t make sense. You probably can’t hide behind a Vat of Acid, but a Chain Link Fence is effective protection against a baseball bat, probably preventing the attack altogether.

When someone’s using a block as cover, decide whether it mitigates or negates the attack. If it negates it, the attack simply isn’t possible. If it mitigates it, the defender adds an Armor rating equal to half the block’s skill rating (rounded down, minimum 1).

Use blocks sparingly. Blocks make it harder for PCs to take certain actions—so they can be frustrating if you overuse them—but they can also lead the players to think creatively. They may see an opportunity to turn blocks to their advantage. If they figure out how, let them!

Sometimes players will just want to remove blocks outright. To do so, make an overcome roll against a set difficulty equal to the block’s rating plus two.