One trick is not to put flock/spackle/dirt on parts of the base, and instead sand it down, then glue small hemispheres (like half a plastic BB) onto it, then paint it green, to make it look like swamp gas is bubbling in the water. Make sure its glossy.
Also, you can cut the figures off below the knees, then glue them to the base, so they look like they’re sunk into the swamp water.
zoinks! yeah, those rock… that whole battalion looks very cool… very active… I love the slime look! and yeah, looks pretty easy too… same pvc glue technique most likely…