This game is a legit way to potentially win money, but it's best if you enjoy shooter games, and that's the primary reason you play. Then any winnings are a fun bonus. Keep in mind that while the app is legit, you might lose money if you don't win the cash games you participate in.
Bubbles is a 2D action game developed by Williams Electronics and released arcades in 1982. The player uses a joystick to control a bubble in a kitchen sink. The object is to progress through levels by cleaning the sink while avoiding enemies.