Hey, if squad talking in elevators makes them Good, then I also venture forth Portal 2.
(Portal 1 had all conversation end before the elevator went, so, unfortunately doesn't count...)

Energy weapons are more effective against shields, non-energy more effective against physical. In addition, some enemies have additional resistances against certain classes of weapons (such as small arms), which, uh... there's a reason Halo 2 enemies are known to be notoriously bullet sponge-y in places.

The sentinel beam is really fun, especially against Flood (which makes sense). I will give you a note that there are actually 2 classes of sentinel beam in the game, which took me ages to note because there's really no delineation. If a Sentinel Beam is not your active weapon, and you can pick up a new one, it's the second type. Careful if one is your active, as switching might be getting you the other type with less ammo, instead of being guaranteed to just be the same gun with more ammo.

Yeah, there are definitely inferences needed when it comes to knowing where this is. At least the nice thing is that with consistency of design, it is fairly obvious that this is Forerunner.

Indeed. Most things have two legs. Even the telepathic worm colonies. When they could have made that armour look like anything.

"Not leaving any of that in", she says at 23:20, having left all of the last few seconds in.

Yeah, this level wasn't one of my favorites, even having no technical difficulties. I liked it best for the Arbiter's characterization, and the look into the Covenant hierarchy.