If the player completes the game on any difficulty, after the credits you see that the Master Chief and Cortana survived. If you finish the game on the "Legendary" difficulty you can see an alternate ending after the credits.
ɪ f WORD_BOUNDARY ð ə WORD_BOUNDARY p l eɪ ə ɹ WORD_BOUNDARY k ə m p l iː t s WORD_BOUNDARY ð ə WORD_BOUNDARY ɡ eɪ m WORD_BOUNDARY ɔ n WORD_BOUNDARY ɛ n i WORD_BOUNDARY d ɪ f ɪ k ʌ l t i WORD_BOUNDARY æ f t ə ɹ WORD_BOUNDARY ð ə WORD_BOUNDARY k ɹ ɛ d ɪ t s WORD_BOUNDARY j uː WORD_BOUNDARY s iː WORD_BOUNDARY ð æ t ð ə WORD_BOUNDARY m æ s t ə ɹ WORD_BOUNDARY t̠ʃ iː f WORD_BOUNDARY æ n d WORD_BOUNDARY k ɔ ɹ t ɑ n ə WORD_BOUNDARY s ə ɹ v aɪ v d WORD_BOUNDARY ɪ f WORD_BOUNDARY j uː WORD_BOUNDARY f ɪ n ɪ ʃ WORD_BOUNDARY ð ə WORD_BOUNDARY ɡ eɪ m WORD_BOUNDARY ɔ n ð ə WORD_BOUNDARY l ɛ d̠ʒ ə n d ə ɹ ɹ i WORD_BOUNDARY d ɪ f ɪ k ʌ l t i WORD_BOUNDARY j uː WORD_BOUNDARY k æ n WORD_BOUNDARY s iː WORD_BOUNDARY ʌ n WORD_BOUNDARY ɔ l t ɜː n ə t WORD_BOUNDARY ɛ n d ɪ ŋ WORD_BOUNDARY æ f t ə ɹ WORD_BOUNDARY ð ə WORD_BOUNDARY k ɹ ɛ d ɪ t s WORD_BOUNDARY