Ace Combat 04: Shattered Skies (Ace Combat: Distant Thunder in Europe and other PAL markets) is a video game for the PlayStation 2 developed by Namco. It is a semi-realistic combat flight simulator and is part of the Ace Combat series of games. The player takes on the role of the top fighter pilot, Mobius 1, of the Mobius Squadron in the air force of the Independent States Allied Forces (ISAF), fighting against the Erusians who have occupied almost the entire Usea continent after an apocalyptic event in 1999. A massive asteroid, codenamed Ulysses 1994 XF-04 struck Usea, killing 500,000 people and turning many into refugees. Erusea used this as an opportunity to occupy the continent after a prolonged military buildup. The Erusians have achieved supremacy via the superweapon Stonehenge, a battery of railguns which was originally designed to destroy asteroids but has been found to be effective against airplanes as well, due to the massive shockwave it releases when it fires. Consequently, ISAF has been pushed back to the eastern coast of Usea

Unlockables

Alternate colors-Ace locations.
To unlock the alternate colors for the planes there is an ace placed in each mission that you must find and shoot down. Here are the planes and locations for each mission.

1. F-5 just north of the allied airbase

2. A-10 north of the enemy airbase

3. F-16 South of the second radar station (the westernmost one)

4. Mirage 2000 Northwest of the westernmost radar jamming plane

5. MIG-29 South of the far western pumping station on the map

6. F-14 North of the northern group of enemies on the map

7. TND-IDS North of the solar tower

8. F-18 after refueling during the mission the ace will appear to the east of the main combat area

9. F-15C North of the center beach combat area

10. RF-01 Far upper northwest corner of the map, northwest of the sub base

11. SU-35 The ace will appear with about 90 seconds left during this mission

12. F-2 North of the Stonehenge gun base

13. F-15E After clearing the radar balloons, enemy fighters will appear; the ace is in the north east

14. F-22 Ace is in the north east of the map

15. EF-2000 Ace will be in the center of the map when the mission starts (between the two southern combat zones)

16. F-117 Ace is located northwest of the westernmost combat zone (Due to stealth sometimes hard to find, head 2 grids north and 1 west)

17. F-15A Ace is located in the far northwestern corner of the map, past the city

18. S-37 The ace is located north of megalith.

The F-4 is available after completing hard mode; the X-2 is available after completing expert mode.

The aces are sometimes difficult to spot on radar as they don't show up until you get close. When you do find them they will be red on the radar instead of the usual enemy fighter colors of yellow or orange.

More Unlockables
Ace Difficulty - Beat the game under expert difficulty

Acquire second color scheme - By completing each mission in normal difficulty with an S-rank you unlock the secondary color for each fighter. By shooting the aces you get the 3rd. It is not necessary to pass the trial missions for the 2nd colors.

Expert Difficulty - Beat the game under hard difficulty

Get All Three X-02 - First, beat the game on Hard with ''S'' ranks in all missions for the gray X-02. Do the same on Expert for the black X-02 and the same on Ace for the white X-02.

Secret Modes - You can get secret modes by defeating the game. Finish the game in any difficulty to acquire Special Continue, Trial missions, FMV sequences, 36 tunes from the game and be able to change the color of your aircraft.

Unlock All Aircraft - Complete the game on normal and get an S rank for every mission to unlock all the aircraft, including the X-02 Multirole fighter. This fighter is perfect for just bout any mission.

Unlock Third Color Schemes - Each aircraft has a third color scheme as well, but these are harder to get.

You have to defeat the enemy 'Aces' that are hidden throughout the missions. There is at least one Ace per mission. They're hard to find.

View the FMV opening with selected plane - You can do this with all planes and different colors. First go to the start mission and select the plane, after that you'll see the weapon menu. Exit the start mission and go to the title.

X-02 Color Schemes - To get the first color scheme for the bonus aircraft, the X-02, get S Rankings on all missions on Hard difficulty, either in Story or Free Mission mode. For the second color, play through the game and get S Rankings on all missions on the Expert difficult.

Secrets

Hidden planes
SR-71: In shattered skies it is the plane that you are targeting at the beginning. Also it is on the Southwest most corner in Whiskey Corridor.

XB-70: This is at the top left corner in breaking arrows.

We've got some gameplay footage for you, so here's mission 8 for those that didn't get there, yet: