Another change I find curious is the aircraft choice. I’m not sure if it’s the fact that some aircrafts from A e Combat 2 are outdated by modern standards, or some licensing issues, but while previously you started with F4, now your starting aircraft is F16, which was present in the original game, but was more of a midgame option.
Also something they probably could afford because they were using the Assault Horizon engine is cockpit view. It didn’t exist in the original, and I love it.
Ace Combat 2 came up with the concept of unique enemies, but they were low key, easy to miss. Here, they are in your face, introduced with a cutscene, and an entire squadron of them (5 planes) each time. Also, each seems to have a gimmick. For Beast Squadron, for example, they are invincible when they are together in the same zone, so you have to lure them one by one.
The entire economy has been rebalanced. There is less planes, and those are harder to buy. I skipped MIR2000, because I wanted to save for F14.
They tried to modernize some missions. The ravine mission where you need to hit the submarine is not a chase after the sumbarine, before it hides in the dock.