360 degrees: the player is finally able to look into any directions to keep track of enemies or just look at the scenery. With the ▲ button the player can now keep track of its target, a functionality which would become a mainstay of AC.
Automatic pilot: rudimentary in its implementation here, later entries featured an autopilot function that worked as one would expect.
Characters: with 10 distinct characters this was another considerable jump from the 2 AI wingmen in AC2.
Design: this is when the series matured, leaving behind its purely arcade-style roots. No longer content to aping real world locations and aircraft, this would be perhaps the most design-oriented entry of all Ace Combat games, with a fully-realized futuristic world. Graphics, audio, story and gameplay are all weaved together to form AC3E.
Endings: 5 unique endings that contribute, each in a different way, to the overarching story.
Freedom of choice: though mission branching was not one of AC3E's innovations, the ability to make crucial decisions during a mission was. As it turns out this is the game where these choices can have the most impact, sometimes completely changing the rest of the game instead of one or two missions. Future installments would reduce the extent of these choices or use a completely different system to give the player more freedom.
Idol: first and only AC game to feature a live-action idol.
J.C. Staff: NAMCO's collaboration with this particular animation house began with AC3E. They were in charge of in-between animation.
Logo: first time the Phoenix logo was not used in any way, shape or form. (added on 11/15)
Movie-style cut-scenes: with plot and characters come both anime and 3D in-game cut-scenes to drive the story forward. The staff's cinematic sensibilities were finally allowed to shine, and in a big way. AC3E still has some of the franchise's best and most unique moments.of airplane action and drama.
Optional loadout: the player can now choose what kind of guns and missiles he wants. Both ballistic and energy-based weaponry are available.
Plot: for the first time in AC there was a story that went beyond an opening text scroll.
Recon mission, M21 TARGET ACQUISITION: first mission where the player is given a special "weapon," in this case a laser targeting pod, in order to reconnoiter a certain area. Non-essential targets can be destroyed but are completely optional.
Soundtrack: this was the first game to get an official soundtrack release. Though evidence of a then-common in-game "Music Player" can still be found in the game's files, it can be assumed that this feature was removed in order to give more incentive to buy the separate OST.
Tunnel mission, M51 TUNNEL VISION: a variation of the original canyon missions from earlier installments, the concept would become a staple of the franchise.