Phantasy Star 2

Slow motion:
Pause game play while in the countryside by holding Start + B. Keep B pressed to move in slow motion.

Pause game play, then press C to advance one frame at a time.

No opponents in dungeons:
Continuously press C to display the control menu and B to close it while holding the D-pad in any direction.

Hint: Shortcut:
After leaving the second town (the one the bandits destroyed), go west along the bottom of the isle to the side of the tunnel. The side of the tunnel is a secret entrance and saves either a long trip back, or 60M for the teleporter.
Information in this section was contributed by Marvin Cox.

Hint: Zema slowdown:
In the town of Zema (a resort town), after the biolab, the people are all tourists or elderly, and will habitually block the bridges and paths in town. Patience is a plus.
Information in this section was contributed by Marvin Cox.

Hint: Visit Zema and Kueri at the same time:
Due to the fact that the monsters in and around Zema and Kueri are very similar, the game allows for both cities to be visited at the same time. Use this to get better armor and weapons, get and level up Kain the wrecker, and level up your party twice as much, making the dump tower (Roron ) much easier to defeat.
Information in this section was contributed by Marvin Cox.

Hint: Easy Ceramic Knives:
When Rolf is at level 5, he needs to level up to go to the abandoned building where the "scoundrels" are hiding. The knives he is using are almost useless. The Ceramic Knives in the second town have a hit value of about 25 points for most enemies, but cost 2800M. To buy these knives, build your characters EXP and M around the abandoned building. The monsters here have a value of about 80 to over 100 M most of the time, allowing the knives to be bought just about the time the characters are ready for the abandoned building. This also allows you to buy Rudo's Sonic Guns and Shotgun.
Information in this section was contributed by Marvin Cox.

Hint: Amy with knives:
Contrary to other sources, Amy can use knives. To best suit her abilities, pair the best knives in the Aria with her best shot weapon. Also use knives until a decent shot weapon becomes available.
Information in this section was contributed by Marvin Cox.

Hint: Saving money:
When the doctor charges large fees to heal, go to Paseo (the first town), where the doctor only charges a small fee. You will also be in Paseo if you are using the Visiphone and the Ryuka Technique, or retrieving Shir the thief when she steals something.
Information in this section was contributed by Marvin Cox.

Hint: Stealing items:
When you get Shir the thief and she is leveled up properly (about level 10) take her to shops. When the text finishes appearing on the screen, press B(2) to leave. Repeat this until Rolf says that Shir is gone. Go back to Rolf's house and she will be there, and the item she stole will be in her inventory. Use this trick in the Central Tower in the first city for the Visiphone, and in the second city (the burnt out one) for the Fire Staff. Shir often finds rare items, but you must have patience. She only steals at random, and has a knack for grabbing daggers and other cheap items first.
Information in this section was contributed by Marvin Cox.

Hint: More battles:
When walking around the countryside, enter battles to gain experience points and Meseta is simple. To do this, walk around in circles, lines, or no desired pattern. You will eventually get placed into a battle.
Information in this section was contributed by V2freak.

Glitch: Catman:
Look closely at the Catman on Uzo Island. It is actually a shapely Catwoman.
Information in this section was contributed by Marvin Cox.