The Glock 17 was replaced by a Beretta 92FS, the Colt Python by a Colt Anaconda, and the MP5 submachine gun by a Colt Model 727 assault rifle. This included some notable changes to the game's original arsenal.
In addition, all of the weapon models were upgraded as well. The upgraded character models in the High Definition Pack included the scientists, security guards, and HECU soldiers, as well as several of the Xen creatures. Subsequently, while the models are improved in terms of the level of detail, it remains a matter of opinion as to whether they look better. However, despite the increased level of detail, the style of some of the models, most noticeably the HECU soldiers, has been changed. The improvements coming from the High Definition Pack mainly stem from the increased polygon count over the default Half-Life models.