I was a Halo Fanatic, I bought the game when it first came out Halo: Combat Evolved, and i also enjoyed the rest of the Saga up until Halo 4. Now there are many specific reasons why which i hope you can take on board because everyone loved the first 3 halos, i thought it was a great story and the game play was good.
Things that could be improved
I think you should revert the New Master Chief Armour back to the one used in Halo 3.
Add the Armory that was in Halo Reach, it was very fun getting certain pieces.
Make the Story More Exciting and in different places except for the same uses of colors and enemies.
Make the Arbiter Come Back!
Make the Ending much more energetic and the Cutscenes in which you play could be longer.
Make the Enemies less repetitive, it's like i can read what they are going to do.
Things i Did Like!
The New Cutscene Gameplay (Press RB to Hit Back, ect)
The Graphics was superb
The New Enemies Design i thought was very good and the boss looked epic.
Thanks for taking this into consideration
~ Brad
