The game is good! You have to choose your enemy based on their bounty. The gameplay is fairly simple and the controls are easy to use. Using your left screen, your character will move up and down the platforms and your right side of the screen is used to fire your weapon.
Personally, I recommend to new players to start with the $100 bounty because its not that difficult to fight enemies with that bounty level. You need to consider the cost of upgrading your weapons and skills in order to progress your character improvement.
Overall, the game is good. Highly recommended for players looking for casual games.