You're right, it does need some gray, and maybe even some yellow.
Off Topic: This is the level plays on: http://www.youtube.com/watch?v=1pLC2BIXaSk
I don't know about the yellow...
But the logo needs to be more centered, the round thingy must be covering from the M to the S fully, the S is sticking out.
Also, the S needs to be smaller as it is a bit bigger then the rest of the letters, further i can only bring up something like a grey rectangular spanning from both above as underneath the letters.
Like in the attachment.
(If the letters are fully within the circle it may look a lot better. Just try and see if it is worth it..)
But these are just ideas.
Off-topic: You sure like MechWarrior.
Double Off-Topic: I'm now off to bed. Cya guys later.
