I've done the first seven missions and I feel like I've played through the exact same corridors from start to finish.
I'm now going through Halo CE and I know there's a decade between the games and I know it's the first in the series but holy shit it's BAD, like 3/10 level of bad. Pretty fine game, particularly the last few missions. Setting aside all the awful technical difficulties of the port, I still managed to play Reach in coop in its entirety. I'm currently discovering Halo games with the MCC rollout on PC.