You can get free coins by watching ad videos, and you should definitely do it if you're serious about the game.

When you're faced with a group of enemies, the best way to engage them is with a few shots or a combo, followed by a jump as they'll end up firing off into nothing.

Combo and sucker punch moves are great choices when choosing your upgrades.

You can swap the buttons from one side of the screen to the other if you are left handed. Just tap the gear icon (settings) in the bottom-right corner in the main menu and then tap on controls and choose "Left Handed".