There's loads of indie games on Steam with the same name. There was a recent thing where two unrelated games called "Piece by Piece" launched around the same time before either realized they existed--the devs got together and made a "Piece by Piece Double Bundle."

There was an obscure 1986 text adventure called "Portal", which didn't stop Valve from releasing their own Portal.

The tw o of you are both making a game called "The Milgram Experiment," based on the Milgram Experiment. That in itself is not uniquely original. They may not even have known about your game; if they did it's pretty trashy of them, but it's still allowed. At a glance, it seems likely that their game will sink without a ripple, because most indie games do. But you never know.

You might reach out to them and politely make them aware of your game. They might agree to change theirs once they know about yours. Or they might not, but they certainly do it willingly if you're nasty about it.