Earth's Special Forces or ESF for short is a Dragon Ball Z total conversion of Half Life 1.
You are able to select one of 9 different Dragon Ball Z characters and use them to blow your opponents away with KI attacks or simply punch and kick them to death with the unique melee system that is designed for fast game play. But don't mistake ESF for a fighter as it is a third person action game with full 3D freedom of movement.
The characters you can select are Buu, Cell, Frieza, Gohan, Goku, Krillin, Piccolo, Vegeta and Trunks. In version ESF 1.2.3 each character has 1 transformation that you have to unlock, but it gives you a significant strength and speed boost. But since the workings of ESF are designed for speed you should make a note that while learning the workings of the game is as simple as reading the manual provided with the game, but actually perfecting the tricks requires a lot of practice. So don't be discouraged if you join a server for the first time and you die a lot. But while ESF is not easy for beginners its unique game play is something that should appeal even people who are not fans of the anime.