Research and Development is a puzzle-centric mod for Half-Life 2: Episode Two featuring an unarmed player but plenty of violent mayhem.
The puzzles are brilliantly designed with a clear goal in mind! The lack of custom content didn't detriment my playing experience, and I simply loved this mod. The fact that you can kill things without a gun just makes it all the more better to see happen. You've really raised the bar with HL2 mods and, more importantly, your mods!