Barrels

Barrels (once revealed) can be activated to cause an explosion that instantly destroys all Monsters on adjacent tiles. Every Barrel also reveals loot after its used.

This mechanism can give a type of Cool-down bank. Every unexplored tile surrounding the Barrel can be essentially ignored since any Monsters appearing in these tiles can be instantly destroyed. Thus once a Barrel is revealed, any unexplored tile adjacent, the explosion activation itself and the loot underneath can be a source for cool-down.

These types of cool-down bank has a drawback. As any Monster is revealed, it blocks adjacent tiles that are in range of the Barrel. Thus the barrel can only instantly kill Monsters that are adjacent to it but not adjacent to each other. Once exploded, the rest of the Monsters in the range of the Barrel can be revealed (except the Barrel has been already used). This is not enough of a drawback to forgo the use of the Barrel and all surrounding tiles as a cool-down bank but should be kept in mind.

The example picture shows a Boss Monster covering 2 tiles to the south of the Barrel. In order to make a proper cool-down bank with the Barrel, the Boss needs to be destroyed first. Then the tile to the left (west) of the Boss needs to be explored and if a Monster is revealed there, it needs to be destroyed as well. Once the 2 tiles to the south of the Barrel is secure for exploration it becomes a cool-down bank of 3 tiles, the Barrel explosion and the loot revealed under the Barrel (potentially 5 cool-down actions). There can be more if loot is revealed under the unexplored tiles (even under a Monster) and less if a Monster is revealed to the south before both tiles are explored. The biggest danger is that there are Monsters on BOTH south tiles and the Barrel can only destroy one of them (this is the same as normal exploration though).