Very true, but 2009 Wolfenstein isn’t underrated. It’s exactly correctly-rated.

That badly. Updates made it better, though.

The MIT is, but GPL is actually very restrictive. For example, it disallows publishing derivative works without those being licensed under the same terms (or newer GPL versions). That’s why commercial companies are reluctant to use GPL-licensed code in their products.

Just FYI, most open source software is not in public domain, it is protected by the same copyright we are talking about here, except the author made it available under certain conditions (the licence).