I'm gonna give you guys a sneak peak to my current project, which is sadly still nameless. I'll get right down to business and show some screenies.
Note that the sequence in which the mission plays out is subject to change, for example, the scenario described below will in fact not be the way the mission starts when it's done.
Scenario:
So you'll start out assaulting a covenant controlled forerunner structure:

It will be a tough uphill battle:

After you clear the area:

You will get reinforcements, including stationary gun turrets! The covenant will unleash a strong counter though, including banshees (not in pic though):

Well that's it for the first glimpse at the mission, obviously the mesh you see here is not final, and is being upgraded as you read this. This is a big project and I still expect this to take at least another half year to finish.
In the mean time, please post constructive criticism and suggestions!
With love,
L0d3x