Martian Deathtrap — Lawrence Watt-Evans

MARS ATTACKS(c): Cards, comics . . . and now brand-new, all-original novels of unthinkable terror!
MURDER MANSION
The invasion was quick and merciless. Nothing on Earth could counter the superior technology of the interplanetary aggressors. Their first strike left worldwide defenses utterly useless. The unbeatable Martian war machine swept the countryside, spreading a reign of terror in every direction. And one small group of humans sought safety in bizarre Gelman mansion built by an eccentric millionaire.
MARTIAN DEATHTRAP pits a desperate band of human defenders against a merciless Martian Death Squad. The battleground is a huge mansion filled with a labyrinth of secret passages with giant insects--and certain death-- lurking outside. For the Martians, the mission is to secure the captured ground by whatever means necessary. For the humans, the goal is to beat the odds and simply
survive . . .