Halo 2

I remember disliking Halo 2 back in the day. Back coming to it now, right after Halo 1, can see some major improvements.
First, they’ve got rid of health system. Now there are only shields, so you don’t have medkits to manage. Also, the shields recharge faster, and they make sure to let you know that.
The weapons make more sense as well. SMG acts like a former assault rifle, spraying bullets, while the new battle rifle fires in bursts and has a scope. Shotgun is still there, but slightly weaker, it seems, as it was a superweapon in Halo 1.

There are also stationary machine guns that you can man. In this level there are clear Iraq influences, which happened in 2003. Halo 2 was released a year later, in 2004.
The Scorpion tank went from feeble to invincible, you can crush whole Covenant armies with it. It fires four times as fast, and the infantry also has homing rockets, if it wasn’t enough.

Covenant have their Beam gun, basically an energy sniper rifle. Considering how powerful the sniper was in the original Halo, that’s a welcome addition.

One episode that is still genuinely impressive is boarding of the Covenant walker, as it walks under the bridge. And that’s without any scripts.