The side-effects will be noticible when you progress further. With my friend we managed to upgrade our weapon into a machine-gun. There is this funny math going on when you pick up power-up and health. It will not only upgrade your weapon for 7 seconds but it will slightly improve your shooting rate and turn rate persistently.
Viewing post in The Grand Escape jam comments
Got it. I completely didn't notice the treasure chests the first time I played. In my mind I guess they were an obstacle to avoid like the driftwood. There should probably be some indication that the treasure chests are good and you want to bump into them, like a glow effect or an animation, or something.