入替人-ReplaceR- on Steam
It's a 2D action shooting adventure game where you switch between multiple guns and use interchangeable gimmicks to try to break through the stages! What awaits you in a mysterious facility in a corner of the universe?
store.steampowered.com
from the source:
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.