Comment 1 for bug 1617456

The keyboard issue is to do with grabs. Games should be able to "grab" the keyboard and receive all events without the shell intercepting Super and Alt. Although a key combo to escape from buggy apps is also required (e.g. Ctrl+Alt+Delete).

Historically Unity7 has done this (better than Unity8 but still) poorly, but that's just a side-effect of Compiz using the Xkb extension which is a bit broken by design (it explicitly does not honour grabs even when you use them).

This is however not a gaming-specific feature, so really should be requested separately. I suggest you split this bug in two.