Removed scenes & concept art from various games

Your textI always wondered why the following concept art never made it in the following games, as they looked very cool:


Half Life 2
I remember when I 1st saw this scene, I thought it would have been quite tough & challenging to fight and avoid these Hydra creatures.
I wish they had made it in the final version of Half Life 2.
http://img222.imageshack.us/img222/1572/hl2hydra.jpg



Unreal 2
This scene were the marine is performing a space walk on an asteroid belt around a Red Giant Star is so cool! It’s a real pity they never included this stage in the final version of Unreal 2.
http://img22.imageshack.us/img22/1059/unreal23.jpg


And is this a Boss of some kind, frying the Skaarj warrior just before fighting you?
http://img718.imageshack.us/img718/1507/unreal24.jpg


And what is this jelly-fish alien thing? They would have looked great in a water stage, but as far as I remember, there was no true water world in Unreal 2. So where were these aliens supposed to have appeared in the 1st place?
http://img6.imageshack.us/img6/9060/unreal22.jpg

http://img694.imageshack.us/img694/6867/unreal21.jpg


And did a smaller version of this appear in the final final game? It looks a bit silly imo.
http://img190.imageshack.us/img190/9877/unreal25.jpg



Doom 3
There were various scenes removed from the final version of the game, for example:

I don’t remember this scene with the pinky demon immerging from the fiery inferno.
http://img684.imageshack.us/img684/2691/doom307.jpg

http://img406.imageshack.us/img406/5240/doom306.jpg


Also did these guys actually appear in Doom3? I only remember them in the Expansion pack “Doom III - Resurrection of Evil”
http://img338.imageshack.us/img338/8443/doom311.jpg


And these scenes in the Hell stage of Doom3?
http://img179.imageshack.us/img179/1252/doom303.jpg

http://img199.imageshack.us/img199/1306/doom304.jpg
http://img641.imageshack.us/img641/2263/doom305.jpg


What is this bird-demon dude?
http://img72.imageshack.us/img72/4060/doom309.jpg

http://img32.imageshack.us/img32/8500/doom310.jpg


What ever happened to the Spider Master mind Boss & the lost souls?
http://img202.imageshack.us/img202/1218/doom302.jpg

http://img684.imageshack.us/img684/6403/doom301.jpg


And finally, I never understood why they removed the infamous “bathroom scene”?!
http://img232.imageshack.us/img232/2095/doom308.jpg



Prey
I have completed Prey, but I don’t remember any of these guys? Please, correct me if I’m wrong …
http://img571.imageshack.us/img571/1237/prey1.jpg

http://img171.imageshack.us/img171/2744/prey2.jpg

http://img29.imageshack.us/img29/2033/prey3.jpg

http://img191.imageshack.us/img191/153/prey4.jpg

http://img442.imageshack.us/img442/9697/prey5.jpg

http://img256.imageshack.us/img256/5117/prey6.jpg



Quake 4
Over all I thought Quake 4 sucked, but it’s a real pity they never included these scenes in the final game:

This would have been an awesome boss. Just look at the batteries in the back, they’re actually tormented marines! That is so cool, in a sadistic, sick kind of way!
http://img100.imageshack.us/img100/6397/quake42.jpg


I think these guys made it in the final game, but they removed the 2 torso batteries from the bottom. Pity…
http://img202.imageshack.us/img202/544/quake45.jpg


This Strogg-Tiger think, looks so fierce!
http://img202.imageshack.us/img202/2776/quake44.jpg


The dispersal plant in the final game looked nothing as revolting or sick as this. Pity they didn’t do it like this in the final.
http://img301.imageshack.us/img301/6375/quake47.jpg


What is this mech?
http://img208.imageshack.us/img208/3255/quake46.jpg


Lol! This chap looks so miserable! I wonder what he was replaced by?...
http://img29.imageshack.us/img29/4805/quake41.jpg


This platform looks awesome. It would have been cool seeing this in motion.
http://img704.imageshack.us/img704/7128/quake43.jpg


So, any thoughts, opinions or answers concerning my queries, will be highly appreciated.
Also if any of you people have any more scenes or concept that didn’t make it in these games or others, feel free to post them here.