You can now select your ship on every stage, and the difficulty of 5 stages has — FORTRESS DEFENDER Steam update #271833
Added the ability to select your ship after clearing a stage. In normal mode, the volcano on stage 5 will now give out items. Adjusted invincibility...
Added the ability to select your ship after clearing a stage. In normal mode, the volcano on stage 5 will now give out items. Adjusted invincibility time when acquiring items in normal mode and above.