The gameplay in this game made halo 2's cliffhanger seem perfectly understandable (especially the Cortana level).
Halo 3 isn't all that challenging unless you play it on legendary by yourself. If you play this game alone things might be more fun if your a soloist, but for those who aren't; you can play the campaign with people or against people over xbox live. All in all Halo 3 is a really great game. The war from Halo: Combat Evolved to Halo 3 is very worth your while abd worth the time and money to play through and triumph. Get Halo 3 and finish the fight.