Shoot enemies and earn money to upgrade your weapons with the non-linear upgrade system. Enjoy the 6 free worlds that each contain 45 levels over 5 different game modes.
Controls:
Move: WASD or Arrow Keys
Aim: Mouse
Shoot: Left Mouse Button
Special Weapon: Spacebar
Change Weapon: Shift or Q
Pause: Esc or P
Build Up 
Garden Secrets Hidden Challenge 
Presidential Protection 
Save The Sheriff 
The Best Pizza 
Age of Giant 4 
Mahjong Black and White 
Ufo Run 
Bugs Got Guns 
Maxims Seaside Adventure 
Desert Attack 
Fighter Combat 
Fairytale Annihilation 
Nails Of Jurassic 
Beach Mahjong 
Zombie Can’t Jump 
Glow Solitaire 
Knock Out Memories 
Hidden Objects Pirate Treasure 
The Spirits of Kelley Family 
Hell Diggers 
Hunter Willie 
Chin Up Shin Up 
Penguin Word Twist 
Daily Heggies 
Wild West Solitaire 
Space Bounty 
The lost planet: Kepler-186f 
Valentine Link 
Battle Card Epic 2 
Loved Monsters 2 
A.L.I.A.S 3