Originally Posted by Bronxsta
How do or can you manually activate the power-ups you collect? I know weapon upgrades are automatic but what about the others like EMP, shield, etc?
You can manually activate stored power-ups by touching the screen with two fingers. This includes the finger you use to pilot the ship, so while controlling the ship with one finger, just tapping the screen with a second finger will use your stored power-up.
If you have a power-up stored, it will automatically trigger when you have no health left. It actually cancels the bullet that would otherwise have killed you.
Hope this answers your questions