With the Definitive Edition update, which has been available free of charge since yesterday, the developers want to ensure a better, graphically revised and even more entertaining version of the original game. This not only includes new character models and textures, the entire lighting and particle system is becoming more dynamic and even the level design has been partially completely revised and optimized. The gameplay has also been refreshed in some areas of the level so that it is on the new standard with the Xen Chapter update.
Furthermore, the balancing of the opponents received a fresh cell treatment, these were repositioned in the levels together with health packs and ammunition. In addition, various optimizations throughout the entire game ensure a significantly better performance on less powerful computers.
In order to enjoy the Definitive Edition, you have to be in possession of the main game Black Mesa on Steam. The complete patch notes can be viewed here.