Halo 1 basically sold the Xbox as a console. At the time, it had a very impressive campaign, but also was a huge multiplayer success. As far as why, the controls are tight, the music is great, the story is good enough, and overall it just has a lot of polish.

Why is Halo Reach so awesome?

It almost made you feel attached to the planet, and in such a short space of time. Reach has given me more replay value than any other Halo game. Replaying each mission never felt monotonous or boring to me. Perhaps this was because of the dynamic and diverse range of levels throughout its campaign.

What is so great about Halo?

It was originally so successful because of the original graphical integrity, being a launch title for the original Xbox, and for being around before CoD could hog the show. Plus great mechanics, fun Co-Op gameplay and a fun (and surprisingly deep) story. These together made Halo into a juggernaut.

What made Halo unique?

These Halo games offer the experience of being a hero, fighting impossible odds, winning battles, and even saving lives. They also offer a distinct flavor of experience, one that communicates desperation, the experience of being overwhelmed, the experience of fighting battles against opponents you know you cant beat.

What is Halo known for?

Halo: Combat Evolved is also noted for its intuitive control scheme that has been used by many console first person shooters since. Halo 2 sold 2.4 million copies making US$125 million in the first 24 hours after its release beating the record for highest grossing entertainment release.

Are Halo games worth it?

Its definitely worth it. The original trilogy was amazing and still is. The original trilogy defines the franchise and are some of the best games out there. Its great run to play through them on MCC, as they all run at 60fps and have 1080p, CE and 2 also have anniversary graphics.