In-game reset
Hold L1 + L2 + R1 + R2 + Start + Select during game play.

Skip Previously Watched Scenes
Press Start + triangle, to skip a scene you have already watched.

Decoder #8:
When you visit the Dock Colony for the first time, a woman in front of the clinic tells you of a Fish Detector that her husband lost. Go to the Kukai Foundation's cleaning place and inspect the tuxedo to find the Fish Detector. Talk to the girl in the Iron Man bar, sitting at the lower left table. She says that she lost an important ring and asks you to find it. Go to the Private Beach and go in the water where the fish show up on the radar screen. Run up to every fish and press Circle. Sometimes you will get an item, and sometimes you will not. You can get a Med Kit, a Speed Stim, and the Engagement Ring. If you return to the beach on any return trips, the Med Kit, and Speed Stim will be there again. Give the ring back to the girl in the bar. She will give you the Decoder #8 to open the red door.

Hazardous Area Map:
On board the Elsa, you will see the pilot walking around in Hangar 1 (A.G.W.S. hangar), looking for a map. He does not give any concrete details, except to look everywhere, and that the captain wants it. To get the map, speak with the captain on the bridge. He will give it to you to take to the pilot.

Easy cash:
Get the Casino Card from the Durandal's Casino (north and east of Shione's room on the Durandal). Then, play Poker. Start with 100 coins (900 bucks) and play level 1 until you get about 200. Then, move straight to level 3 until you get about 700. Then, play level 4. The way to always beat the house is as follows. Always hold a pair or any other scoring combo. After you win, always do double or nothing. If the number is greater than 7 bet low, if the number is 8 it is your choice, and if the number is 9 or above it is best to go low. After accumulating about 45000 coins, get 99 starter decks of cards and sell them for 20,000. It takes a total of two hours to make about 100,000 (and all the prizes and art.)

Game completion data:
Once you complete Xenosaga: Episode 1, after the ending credits roll, the game will ask if you want to save. Answer "Yes" and the game completion data will be saved. Although you cannot load this saved game data with the Episode 1 game disc, do not delete it. It is likely that this game completion data will be used to load your characters stats into Xenosaga: Episode 2.

Gargoyle
You have to face Gargoyle in the Gnosis Cathedral Ship. The Gargoyle actually Commander Cherenkov. You need to have Shion, chaos, and KOS-MOS fight. Make sure that you have the upgraded frame and generator parts for Shion's and chaos's A.G.W.S. units. Equip both A.G.W.S. units with a sword since the Gargoyle and other Gnosis aren't good against close range attacks. Make sure everyone is at least level 18 or higher. When the battle starts, get into the A.G.W.S. units, and only attack the Gnosis on the right until it is dead. Why the Gnosis on the right? Because it can heal the Gargoyle 600 hp every turn. Then have KOS-MOS use med-kits on herself until she is fully healed. Finally attack the Gargoyle.

See Shion or MOMO in a swimsuit
When you are saving the people at the Kouki foundation, there is a chest in the hotel. When you get it, it will say "Swimsuit". You can equip it to Shion or MOMO. This allows their TP reward to increase by 25%. Also, when they are fighting they will be in a swimsuit. If you saw the intermission sequence where they are at the foundation's beach, you will see MOMO and Shion in a bathing suit. That is how they will appear as when they fight with the swimsuit equipped. Also, the same item can be won by completing Mission 4 of the Driller Game. A third and final swimsuit is to be found by defeating Great Joe. Note: Jr. and Chaos can also wear the swimsuit, and can be seen in swimming trunks