| Angel Island Zone
| First level, Sonic the Hedgehog 3
| Number of Acts: 2
| Level theme: jungle
| Boss: Flame Mobile
| Sub-boss: Fire Breath
| Maximum rings, Act 1: 104 + 50
| Maximum rings, Act 2: 306 + 60
| Underwater areas: Both acts for Sonic/Tails,|
Act 1 only for Knuckles
- For the eponymous zone in Sonic Advance, see Angel Island Zone (Sonic Advance)
Angel Island Zone is the first zone in Sonic 3. When playing as Sonic, a somewhat lengthy introduction is played in which Sonic and Tails discover the floating island and first run into Knuckles. An alternate version of the intro had Sonic surfing onto the island, which is a leftover from a beta version of Sonic 3. The surfing sprites can be viewed via debug mode. Nemesis created a savestate with a restored surfing intro sequence, which can be downloaded here. At the end, Sonic and Tails are dropped into Hydrocity by Knuckles destroying the bridge. Knuckles simply jumps off the bridge in S3K.
Instruction Manual Description
||Welcome to the Floating Island. Things will really heat up once Dr. Robotnik sets fire to this area of the island. Beware of the Flying Battery blimp.
||We started development on "3" with a story in mind, but it turned out we couldn't make it in time without problems. In the end, the game ended up being cut in half (laugh). This stage starts off with a certain impact, as the flame thrower machines set fire to the island and change the color considerably.
— Sonic Team, Takashi Iizuka
Angel Island Zone in flames during Act 2.
- In Act 1, when Knuckles robs Sonic's emeralds, it's possible to fly across and catch Knuckles quickly. After that 8 icons of Rhinobot will display and Sonic can go through walls (Example: Sonic can finish IceCap Zone in 1 act).
- In Act 1, if the player attempts to get with Sonic to Knuckles' sub-boss area by getting through the breakable rocks (which only Knuckles can break) with debug mode, after walking a few steps the screen will automatically try to scroll up to Sonic's sub-boss area, thus killing the player instantly. If debug isn't deactivated after getting through the rocks, the screen will anyways scroll up, but the player won't die because it's still on debug.
- On the other hand, trying to access to Sonic's sub-boss area with Knuckles (Debug mode or Super/Hyper Knuckles only) won't make anything happen.
- It's possible to go into a Knuckles-only section of Act 2 when playing as Sonic by using debug mode, then go up to Sonic's path after going through the long set of breakable walls. When you get to the boss, there will be two of them - one acting as Sonic's boss and one acting as Knuckles'. This can be used to give a 50000 point time bonus if you use one of the capsules to trigger the end of level and reset the time to zero, then use the other to trigger another end of level.
- After defeating Act 2's Boss, during the Knuckles cut-scene, you can hold left and repeatedly try to jump. If done correctly, you'll jump off the bridge as it collapses, allowing you to avoid falling into Hydrocity Zone.
- After passing the portion of the level where Angel Island (Act 1) is set on fire, when the player enters a Special Stage Ring or a Checkpoint and eventually leaves it, the background will play the Act 2 music for the rest of the act (and essentially the rest of the stage, not counting the boss battles and the moments after defeating Act 1's boss). The reason why this happens is because, internally, the game has already switched to Act 2. The level being set on fire is simply a distraction while the game internally switches to Act 2, manually playing the Act 1 music in the process. (This was possibly done to change midway Act 1 the green, tropical background from the first act to the red, burning Act 2 background).
- When restarting, there is a special check to play the act 1 music if the starpost following the cutscene was the last one hit, but a technical error in this check means it fails to work, although even if it did work it would still be possible to trigger the bug with Tails if you bypassed the starpost right after the cutscene by flying over it.
- An internal level change with the same purpose also happens in IceCap Zone Act 1.
- As a related glitch, once the player has advanced enough in Act 2, the game deactivates the barrier that prevents the player from backtracking further than the place where the boss fight occurred, the player can then go back as far as the point where the internal level switch took place. While the game still views this as the player remaining in the same level, the player perceives this as actually going back to Act 1, making this the only zone in Sonic 3 & Knuckles that allows backtracking to the previous Act.
- Nearing the end of Act 2, the character will pass through a long twisting tunnel, and if going fast enough will be thrown into the air off the top of the screen when exiting the tunnel. When playing as Sonic using a fire shield, the player can hold right and repeatedly press jump. The jump sound will sound followed by the fire shield sound, and the screen will move quickly to the right, as if there was a platform above the screen from which Sonic has jumped. The level then carries on as normal.
- When you're playing as Sonic and Tails and get near the end of Act 2, let Tails go through the tunnel first. Then after you passed the tunnel, you'll see Tails standing in his roll pose. He will stay like that until he's harmed.
- If Sonic or Tails is positioned exactly between the spikes and the Checkpoint, they will go halfway through, then be pushed back out.
- Rhinobot — A robotic rhino that charges at you.
- Monkey Dude — Just your standard (blue) coconut throwing monkey.
- Bloominator — A red flower with a metallic blue stem.
- Catakiller, Jr. — A blue caterpillar surrounded by a shield-like contraption. Only the head is vulnerable.