Recommend a GoG game

OK, I have most of the RPG and other hits - the Fallouts, Gothics, Sacred, Sacrifice, Spellforce, Duke 3D, Far Cry, all of the Jagged Alliance stuff, Disciples 2, Arx, Stonekeep, Lionheart, Stronghold, Unreal, Postal ...

And I won a free game from GoG and now have to choose. Obviously I want a $10 game to maximize value, and would prefer a RPG or shooter (rather than an adventure or RTS), though a Turn-Based game is OK as well.

Any thoughts?

Redneck Rampage, if you don't already have it.

Neither shooter nor RPG, but the Tex Murphy adventure games are quite excellent. Especially the first two of them.