It would be really great to be able to use key combinations for the Game Keys.

Currently, you can only set a single key in the Game Keys, which means that we have very few keys to work with without having a conflict with a default TTS key. Being able to set Shift+R would mean we wouldn't get conflicts with R for randomize, for example.

You will have to make the choice of whether the Shift, Alt, Control modifier keys will be the "real" ones or if they'll be the ones we're setting in the Configuration->Controls menu, though. Personally, I think using the "real" ones is best since the ones we're setting in Configuration->Controls are tied to certain specific functionalities that some might not find convenient as those keys. Plus, I think players will expect that pressing Shift+R makes Shift+R appear in the Game Keys entry, even if they set it Shift as something else in Configuration->Controls.