Games Like Gunslinger Top down shooter

Gun Slinger is a top-down Shooter game here in each mission there are a certain number of enemies which you need to kill to complete the level.
once you kill all enemies a chopper arrives on the helipad and you need to reach there to complete the level.
In Early Access, The game has 3 different heroes to play the mission .you can select a hero in the character selection screen.

YOUR MISSION: Liberate World from the army of "Mad Scientists".
Our world is attacked by a ruthless killer "mad Scientist". his aim is to drop 300 nuclear bombs on 200 targets in the world,
followed by a massive land invasion that they expected would be over in no time. mad scientist operates his mission from an evil organization on a remote island. He has created weapons of mass destruction and bio-mechanical weapons.
So now it's up to you to go and save the world from the army of "Mad Scientists".