but imagine playing it back in the day and seeing that ending
Imagine indeed..... Halo 2's launch felt like the first HUGE game launch to me. A year and a half spent hyping it up the ass , the infamous "2 GUNS" gameplay reveal at E3 2003 , midnight launches at gamestops across north america.
And then... a week later at most , everyone finishes the game only to notice that the final stage was cut from the game :( This happened the same year that Half Life 2 pulled the same shit. Even though it made the campaign a bit of a let down, Halo 3 became even bigger because of it. Perhaps the cliff hanger would have gone over better if the overall gameplay in Halo 2 was better but... it was weaker in most ways, levels felt more narrow , fewer vehicle portions, having to split playtime between Arbiter and MC. What ultimately saved it was of course that Halo 2 was the XBL showpiece , playing online with voice chat in 8 player matches with some fun maps.
OP, just be thankful that it's now 2020 and you don't have wait 3 years to play the rest of the story.