From a 1980 Kenner in-package catalog:
"From the ice-planet HOTH, an action-packed play environment! Features a collapsing bridge, land mine, exploding command post and movable gun."
Considering the role of the Rebel "Echo Base" in The Empire Strikes Back, it is interesting to note that this toy is the Imperial Attack Base! A more likely title would have been "Rebel Attack Base" but Kenner was careful to include Imperial playsets as part of its line of Hoth offerings.
As the catalog promised, this playset is action packed. The base has a
lever-activated collapsing bridge and button-activated "land mine". The most
dramatic feature is the exploding command post -- at the press of a button (or
hearty slam for those energetic kids) the four pieces of the command post spill
out of the base creating rather convincing battle damage.
The "land mine" is located beside the dark rectangles at the top of the base. If a figure happens to be standing on the land mine when the button is pressed, it will be knocked over. The lever that activates the exploding bridge can be seen in the middle of the right side of the base. The button to activate the exploding command post is beside the other dark rectangle located to the left.