This one honestly surprised me, and it seems like not many people know about it since there's barely any comments in the steam forums.
Ninja game about killing your targets with a bunch of different tools and weapons. It has local coop but if you're solo you can just grab the other ninjas and use them as extra lives when your first ninja dies.
You can also kidnap npcs to play as them and completely cheese the game since guards won't attack you. Kidnapping is kind of annoying though because npcs wake up super quick from being knocked out.
https://store.steampowered.com/app/3634550/Ninja_Game/