Xenocide

Xenocide is a Space Invaders variant. The player's space ship is confined to the bottom of the screen and can only move left or right. The goal is to kill all approaching aliens before they manage to reach the bottom. Right above the player's position are three buildings which keep off attacks, but are slowly destroyed with every shot.

This variant introduced a few additions to this classic formula. First, there are shields for both the enemies and the player's ship which means that not every shot means instant death. The second addition are power-ups which sometimes fall from the top. They give advantages when collected, e.g. speeding up the ship, secondary weapons or a shield boost. After each wave, the game rates the player's performance regarding accuracy and may award additional power-ups. There are also additional enemy types present like big aliens which split into smaller ones when defeated. Classic mode removes power-ups and shields and plays more like the original.