Ground Bases are large ground constructions often found in numbers at the end of stages, though some of them can also be found scattered around stages. They're immobile and come in varying sizes, with each type shooting different types of bullets. Whenever one Ground Base is destroyed, the others will increase their fire rate.
In both games, a timer will appear whec facing the Ground Bases. If they're destroyed within the time limit the player will be given a large point bonus and the game's AI will be reduced; otherwise the AI will be increased.