I'm in. Thanks and +1.

The obvious answer to me is one that has been said many times already: Lemmings.

Starcraft: You sacrifice two templars for an Archon and you can sacrifice a zerg human for a huge explosion

I'm in, and thanks for the giveaway!

*In Skyrim, there is an optional quest to Sacrifice one of your followers on the Altar of Sacrifice and become the new champion. There is another quest which gives you a sword that can only be charged up to full power by sacrificing your close friends, or other people who trust you.

*In the first Fable, you must sacrifice at least one follower to obtain the best bow in the game.

*And in Dragon Age: Origins, you can sacrifice a mother to Blood Magic to save her child from a demonic possession. There is also the Blood Mage spell called 'Sacrifice' which sucks the life-force from an ally, healing the caster but potentially killing the ally.

Very nice! A Sacrifice-Giveaway!
But I´m not in.
Surprised?
;)

In for sacrifice.

I can only think of KoDP, though.

Thanks for the giveaway.

Was going to say Covenant of the Plume, but someone beat me to it.

So I guess I'll say the SMT series (sacrifice fusions)

Not in but +1 :D

Eador: Genesis. You can sacrifice your villagers to the dark gods for precious resources!
I'm in by the way.

Warcraft 2, Goblin Sappers (Orcs), Dwarven Demolition Squad (Humans). These units cause great damage to structures, but self-destruct in the process.

I'm in, +1.

I've been excitedly waiting for a Sacrifice giveaway. +1

As for the question, I'd say X-COM: UFO Defense has a lot of sacrificial gameplay elements to it. Sometimes you're forced to sacrifice the life of some greenhorn rookie bastard on your team to protect a higher ranking, more experienced operative. There's also the decisions to let a particular city or country get overrun by alien invasion in order to lend a hand to countries that give you more funding. It's nerve racking, stressful, and I both absolutely hate it and love it at the same time.

I'm in with Rogue Legacy. Every generation has to sacrifice themselves so their ofspring will be good enough eventually. You just know the first characters will never ever make it so they sacrifice themselves till they finally create a bastard that is strong enoug ;)

You can sacrifice people in Fable for infamy.

Inquisitor.

im in! thanks for the giveaway!
In the SMT series the spell "recarmdra" sacrifices the user to AOE resurrect allies.

Soul Sacrifice: player can sacrifice parts of the body in order to cast powerful spells.