Attack The Outer Base is the 6th stage of Gradius V. This stage is notable in that large portions of it contain acid producing machines, making it a very hard level and difficult to survive inside. After that the Fortress withdraw itself to Stage 7 for using for high speed of part of the stage.
This stage starts out with few enemies at first, but contains turrets in the section with the acid producing machines. On the part before the boss rush, there are lots of enemies that come from behind. Double,Tailgun,Rotating options and Aiming Options are highly recommended for that section.