TREG is a training game which simulates various activities in software requirements workshop technique based on the book "Requirements by Collaboration". It was developed in Second Life, a virtual world that gives the possibility to create an immersive collaborative educational experience. This study evaluated TREG using the usability metrics for games: interface, game mechanisms and gameplay. The purpose of this paper is to present our process and results of the usability tests for evaluating the user experience in the game. © 2010 IEEE.