Its unique and awesome. Hopefully more people find it.

Hi, I'm trying this out for the first time. I get to the very first room and press tab. There are two weapons to choose from, but I'm not understanding how to do so. I hover over the weapon choice and click. I double-click. I hit enter. I hit spacebar. Nothing responds. So when I return to the game, I guess my weapon isn't selected? Nothing I do actually aims or fires the weapon. Any ideas? Thanks....