@Supaserrin
*Spoiler Alert. You have been warned.*
I think the reason 'Christina Lives' was the phrase, wasn't because they Chose it. I think Chris's Mother, in a previous timeline taught a parakeet that phrase for when they would try to experiment with birds.
The only bird who would survive the time travel process would be the one she already taught the word to.
I think she did this to tell everyone that the time travel machine was a success and that she is still alive. Then the bird taught the other birds the saying, and then a couple million birds knew it- but that bird was the only survivor.
Because that Bird time traveled before, because of her mother.
...Probably.
Anyway, 5/5 game, easy. I would love a sequel or prequel, maybe with gameplay in which not everyone has to live or die. Where your own skills and prior knowledge can help you save lives, not just as many lives as the game itself says you can, you know?