Gunz: The Last Duel 1.5

Gunz: The Duel was a fairly average action PvP game back in the early 2000s. However, there were a couple of things that quickly propelled it into popularity. One was the amount of glitches and exploits that it had. Much like Smash Bros Melee,  these glitches took a high level of skill to carry out, but also added a ton of depth to the game. Another reason was that there aren't any other games that featured the level of parkour and combat depth that it did, even to this day. It's officially died off, but there are private servers such as Gunz: The Last Duel that keep it alive.

To install Gunz: The Last Duel, simply run the executable and you're good to go.

The main thing this game has in its favor are the glitch techniques, or what are referred to as "K-Style" in the community. These are a series of techniques where you swap weapons to animation cancel and exploit some of the physics of the game. For example, if you dash into a wall with a melee weapon out, you can slash or stab it while pressing jump. This will make your character backflip backwards, but also cancel the animation of the backflip which would normally lock you until you fall, letting you constantly climb a wall in this manner. Another glitch is the butterfly, where you guard right after slashing in the air - this will put out a damage hitbox and a guard hitbox at the same time, letting you attack and defend simultaneously.

All in all, Gunz: The Last Duel is a faithful recreation of the original, glitches and all.