This modification is a transfer of movements from GoldSource/Half-Life 1 and Source/Half-Life 2 to GTA. Bunny hop, strafe, explosion jump, surf, swim, NoClip and much more are fully implemented, along with a switch to switch between HL2 (ABH) and HL1 (bhop) mechanics and gravity.
Default control: - F7 to switch menu; - Numpad for navigation; - LCtrl + Q to switch the mod without using the menu; - V to toggle noclip.
You can see the demonstration of the mod using San Andreas as an example in the video below: