I remember an old pc game that had zombies and the zombies were green squares and the backdrop was black and there were power up things that would fall from the sky and you would try to survive for the longest time to get a good score and when the zombies would attack you it looked like they were humping you and your weapon was laying mines or something and the powerups would upgrade your mines to have either have the ability to place more mines or make the explosion bigger and have like fragmentation or something. The game might have started with the letter B.
Edit 1. I asked a friend and he said the game was Bombie Zombie
Edit 1. I asked a friend and he said the game was Bombie Zombie