3. Halo: Reach
The prequel of the FPS that redefined the genre, this one boasts the most moving conclusion not just for its self-sacrifice and brilliantly done epilogue, but the fact we all knew even before opening the box and pressing start that it was always going to end this way. Reach is essentially a story about how Chief's best mates all ended up dead while he took a nap. You take the role of one of a squad of Spartan II's, as they get picked off one by one as you all battle in vain to save Reach, the latest planet to succumb to the marauding Covenant forces. After successfully keeping the Covenant forces at bay long enough for the Pillar of Autumn (and a sleeping Master Chief) to escape to the relative safety of a Halo. Once the credits finish the game isn't over and you're left in the middle of it, on your own, out gunned and outnumbered as Elites and Grunts alike close in to tear you apart. You fight as long as you can, you'll run out of bullets, you'll pick up another gun, your shield will fail, your visor will crack and splinter until finally you're set upon by a few Elites with Plasma swords. Finally, a repeat of the shot from the very start of the game of a broken Spartan Helmet, was in fact a double and the game ends. You've done your noble deed. Saved chief, and the universe. But you died.