It's free until 9th of August to add to your account. Is it a good game? I have no idea but apparently it's won a few awards.
From the Steam page:
A 2D action game. It might be better to call it Metroidvania.It's an action game where you switch between multiple special guns that swap things around and aim to step through the stages.
Do I have to click the 'Free to Play' button to add this to my account?