(This should have been a reply to the Sudden Death thread , but it grew too long obviously

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I think the game gives the illusion of balance. To me , it feels broken on many levels - but maybe I just can't appreciate its weird mechanics.
Just like both teams can not be compared easily , game balance cannot be judged so well. If you look at game outcomes , it seems balanced. If you look at kills , the humans seem to have a slight advantage.
If you play the game , the difference is obvious. Humans have overpowered low-skill gear , and aliens have overpowered high-skill abilities. An clever dretch might manage to destroy a single exposed turret by circlestrafing it , if no human is around ; any but the dumbest human can destroy defenses and critical buildings of the usually deserted alien base , either with his no ammo blaster or his main weapon , without taking significant damage (running into tubes makes a vanilla human lose 5-10 hps , while running into turrets kills a vanilla dretch in a split second)
Shooting large aliens doesn't take much skill , the contribution to the team is the same regardless of the skill level. I never saw anyone successfully duelling a tyrant with a rifle or blaster , though I have killed some that way - with sheer luck , just because they didn't master their hit&run technique perfectly , or disregarded their survival while fighting. The only real difference is against the lower alien classes , up to adv marauder. Even then , aliens usually die due to their own mistakes , than due to human skill.
Aliens however , need much skill to effectively score kills (especially through base defenses) when the odds are not ridiculously stacked (vanilla human fighting a dragoon alone)
Most of the new aliens get kills from the deadly "fallout" of other skilled aliens (finishing humans off with luck) , and cannot properly fight otherwise (often accused of "feeding" since they are frustrated to score no kills)
Indeed , headshots do most of the "useful" damage (that which is not likely to be healed moments later) and they require luck and/or skill , in a very counter-intuitive fashion. 1 headshot + any other contact is enough to instantly kill a vanilla human , but dretches running at leg level and not knowing how to score headshots will require 5 legshots to kill , assuming the human does not use the medikit - so he can take up to 9 legshots before he dies , or up to 5 normal hits , and it gets worse with armor. Meanwhile , a dretch dies from 5-6 rifle hits. Newbie aliens are bound to feed if they do anything else than waiting on a remote dark corner.
The difference is more obvious with dragoons :
-A newbie might manage to have 3 evo points when the humans reach stage 2 , and evolve to a dragoon. He may not know , however , that the pulse rifle will kill him in a second or 2. Nor does he know that the lasgunner brings his doom if he has less than 150 hps and cannot manage to kill him fast. He might think that his 200 hps will let him attack turrets , but to his horror they collapse before he can react , and he dies fleeing - here goes his last hope to contribute.
-An elite dragoon is a different story , instant kill with well-timed pounce/headchomps on any stage 1 human , and turrets or other human buildings vulnerable to his clever tactical analysis. I've seen dragoons manage to kill battlesuit chaingunners with sheer skill.
Of course , nothing is safe from a highly skilled adv marauder. Not only they are nigh unkillable (not giving humans any credits , ever) but they are a permanent threat and quickly dispatch those daring enough to actually attack the alien base. Players below the "1337" threshold can only master the first of these skills(so the net contribution to the team is not great)
Another reason Tremulous games are so long is that the alien base is excessively flexible , and the human base excessively strong. Think of a StarCraft game where the zerg can build hatcheries for free , and the terrans can build bunkers for free. It can only end in a dynamic stalemate , where striking the enemy base gives them the advantage , but is necessary to win.
Like it or not , Natural Selection is an important reference if Tremulous is ever upgraded or rebalanced. This game shares some of its issues , but has answered others. As I wrote on the silly Tremulous vs Natural Selection thread , one of NS's strong points is that players of any skill can contribute to their team's victory if they bother to communicate or just listen. It is possible to "feed" the enemy team there as well - but both teams have to move out of their bases to not suffer from imminent , inevitable defeat. Unlike in Tremulous , exploring and exploiting the whole map is necessary to fare well.
Highly skilled Fades are terribly overpowered , more so than in Tremulous. Think of a cross between adv marauder and dragoon - with none of their weak points. Surely it is thrilling to play as a Fade - but it is not funny to stand no chance whatsoever as a vanilla marine (even upgraded)
Still , teamwork works in NS. Players can support each other and not fear TKs so much. Unskilled players can safely and easily build - they cannot possibly harm their team doing so. Skilled players can either fight on their own (a trend I dislike) or lead others in daring offensives.
Marines run slower and cannot easily dodge attacks like in Tremulous , while aliens die faster to accurate gunfire. Besides skulk bunnyhopping , natural skills like aiming and stealth are emphasized.
Both sides are not required to kill the enemy to grow in strength , since resources are extracted for both individual and collective upgrades. NS succeeds at integrating strategy into a first person shooter thanks to this.
I admit that Tremulous will need much work to be fixed (that is , change for the better and not grow new bugs or shoddy tactics) but it is worth it.
I would even contribute to such an effort if asked.