Pre-Fortress 2

Pre-Fortress 2 is a free mod that attempts to recreate the visual aesthetic of Valve's 2006 beta version of Team Fortress 2 as seen in Trailer 1 and Trailer 2 of Team Fortress 2. Its gameplay mechanics takes cues from Team Fortress 2's predecessors, Quake Team Fortress and Team Fortress Classic.

Features

Different grenade variations given depending on which class is chosen (like Team Fortress 2's predecessors Quake Team Fortress and Team Fortress Classic).
Beta Team Fortress 2 graphics and aesthetic (including player models) like in Trailer 1 and Trailer 2.
Beta Team Fortress 2 sound effects.
Armor has been added back (like in Team Fortress Classic and Quake Team Fortress).
Different max health depending on the chosen class, similar to Team Fortress Classic and Quake Team Fortress.
The Engineer can now repair teammates' armor by hitting a teammate with his wrench.
The Spy now has a tranquilizer gun that makes enemies mouse sensitivity high and makes it hard to aim when hit.
The Scout now has a nail gun (like in Team Fortress Classic and Quake Team Fortress).
The Heavy now has a lead pipe as his melee weapon.
The Sniper's default sniper rifle now works like The Classic in Team Fortress 2 (or the sniper rifle from Team Fortress Classic).
The Demoman now has dynamite as his throwable item.
The Pyro can now shoot incendiary rockets by pressing right click instead of airblast.
The Sniper now has a club as his melee weapon.
The Medic has a syringe as his melee weapon that heals teammates and poisons enemies when hit.
The Pyro has a branding iron with the Team Fortress 2 logo on it as his melee weapon.