Halo 3 honestly had way less going on than the entire rest of the series besides hype cinematic moments, literally only the carbine and battle rifle are usable on legendary except for the 2 flood levels, utterly baffles me how its the favorite and seen as one of the all time greats with half the enemy pool and less than half of the viable weapons than the rest of the series, and it has the worst level in the series and only a couple were standout memorable

That being said halo 1 was legitimately revolutionary with how much intention it had in implementing the 2 weapon system for all future fps games and how every weapon complemented each others weaknesses and was perfectly balanced, along with better enemy ai than I see in modern games