Credits...
	Cutscenes...
	Reload...

The credits you earn at the end of each level can be spent on upgrades and items that will help you out in the next.

If you get tired of the interminable cutscenes, tap the screen, then tap the arrow button to skip them.

Reload after every gunfight. You never know for sure what is around the next corner, but it is probably going to try and kill you.