As capturing aliens living (with that weapon)

[Mayhem]

Don't forget that ordinary damage also contributes to stunning.

I've had three orlocks shrug off a gas grenade, but followed it up from a shot from a plasma-armed grenade launcher.  They became stunned rather than killed.

I don't know if the stun rather than kill in this instance is certain, or based on the damage delivered by each, or what.

But it is still a particularly useful thing to know when your stun-rodder has just run up, zapped an alien, and the alien is still standing.  Get another soldier to finish it of with with a conventional weapon and there is a very good chance it will fall stunned rather than dead.

[Sophisanmus]

The Grenade Launcher is already one of the kickassingest weapons in the game, and, to be honest, I'd love to see it stay that way.  The counterbalance, though, should be keeping it stocked with those appropriately awesome munitions...

Stunning probably works much the same way as the old X-COM: a inverse "damage" bar fills up rather than empties when hit; when it surpasses the victim's current HP  unconsciousness sets in. 

[Surrealistik]

Stunning probably works much the same way as the old X-COM: a inverse "damage" bar fills up rather than empties when hit; when it surpasses the victim's current HP  unconsciousness sets in. 

It does. Try injuring an alien before stunning it; the booger goes down a whole lot more quickly.

[Koa Bosk]

Perhaps you could put something in game that you could incapacitate an alien or have there be a slim chance that an alien could be knocked unconscious by weapons fire. On the return trip home when you get the recovery letter have it state "Our live alien containment is inadequate to keep them a live long enough to study, I suggest researching alien breathing" or something along those lines.

[TrashMan]

An energy bola is a little too sci-fi for me, since I can't see how this would work in terms of physics, and a regular bola would obviously be ripped off by these aliens, since they tend to be bigger and stronger that human beings.

Well, it wouldn't be a regular bola, would it?
Use super-strong alloys or  stuff. Some aliens might be strong, but they aren't Superman to break titanium shackles.