MAD's Spy vs Spy

Released 1986

"An explosive tunnel-building game of Risk and Rivalry!" "Build a maze of tunnels to bring home bombs and win the game" "Ages 10 and Up" "For 2-4 players"
According to boardgamegeek.com, "The bombs have various effects hidden on their base. The tunnels are built through tile laying, so each player (best played with four) digs furiously from his manhole in the corner towards the bombs, hoping to reach 'em first. If you connect tunnels, then you'll be able to try to steal another player's bomb before he brings it home."