Content cut, changes in direction, media from games that were cancelled...
Half Life 2 Valve actually cut and changed quite a bit of stuff during development. Most notably the missing creatures from the first game and it' s expansions. The missing enemies are...the Alien Controller, Alien Grunt, Bullsquid, Chumtoad, Gargantua, Gonarch, Houndeye, Pit Drone, Shock Trooper, Vortigore, Pit Worm, Gene Worm and Nihilanth.
Then during the beta phase they cut the Hydra...
...the Combine Assassin, Synths and the Cremator, ...all of which can be seen in
this video They cut weapons too. There was originally going to be an AK47, a OICW (carried by the Combine Soldiers - as shown in the Hydra pic), a handheld Gauss Gun, Hopwire Grenades (which looked amazing), an ice axe, asomething called a Physgun, a submachine gun that looked more like a UMP45 than an MP7, a Heckler & Koch MP5K, player usable Stunsticks, a sniper rifle, a heavy machinegun... and more... all viewable in
this video There were also different characters, places and vehicles cut or changed, all of which can be read about
HERE What other games can you guys think of???