Earthbound
- There's a hidden clubhouse where a kid will give you a cap that's better than anything else available. It's by the library with a kid standing guard so it shouldn't be hard to find. It isn't significant, but every bit helps.
- Don't be afraid to experiment with strange items (toothbrush, ruler) in battles or boss fights. The Eraser Eraser in particular.
- Don't buy the seaside house in Onett unless you're swimming in cash.
- About 2/3 of the way through [the first cave dungeon] is an outdoor area. A PSI Butterfly commonly spawns out there, giving you back 20PP. Keep refreshing the area until you're full, letting you spam Lifeup and (Rockin) to your heart's content. He can be a pain if you don't heal on EXACTLY the right turn or he gets a critical at the wrong time.
- A couple PSI FavoriteThing trivializes the Titanic Ant fight.
- Give Paula all of the vitality capsules you find, she needs them the most.
- Freeze can stop an enemy for a while.
- Fresh eggs will be a great source of income if you hold on to them.
- Here's a good stat grinding trick: If you use a Rock Candy with a Condiment (Sugar or Jar of Delisauce) when it pumps one of your stats, the condiment is consumed, but the rock candy isn't. You can empty your inventory and fill it with nothing but sugar and get a bunch of +2 increases and completely break the game.
- Once you get Jeff, feel free to stock him up with Bottle Rockets. He can't use PSI, so you might thing he's underpowered. Bottle Rockets are key. Expensive, but worth the easy battles.
- Pizza is a heal-all item with three tiers, so calling Mach Pizza can be very helpful in managing the clutter in your inventory.
- The For Sale Sign is also helpful in getting rid of cheap items.
- Use your phone for making deliveries and talk to mom every so often. Your inventory fills up with random junk all the time.
- If you see a red or green caterpillar, chase it with a Skip Sandwich.
- Skip Sandwiches are costly, but moving faster is more rewarding.
- If you meet someone behind a waterfall asking for a password, stay put and make lunch for yourself.
- There is an Insignificant Item in a drawer in Threed Hospital. Take it to the man in Twoson's Hospital and you'll be given a Magic Truffle!
- PsiTeleport can be used to make sudden turns if you are fast enough to control it. Take care not to go too far if you abuse it to run past fights.
- PsiFlash can cause lots of random ailments to enemies.
- Fobbies and Foppies are amazing enemies to grind on and only for a limited time.
- When you get to the Guardian Diggers, leave the third strongest one for last.
- There are a couple places where butterflies respawn if you see them.
- Lots of stuff that Jeff can use is repeatable and his Broken Bazooka becomes his greatest weapon after you fix it.
- Brain Food Lunch is favored by Poo.
- The Sword of Kings is the only "rare" item MAYBE worth the time in getting and from Starman Super. It does factor into automatic win encounters.
- Don't grind Ness to max level until after he defeats his nightmare and gets his powerup.
- The L button does everything in place of other commands like talking to people, searching trash cans, L does it all.
- The total offense of every character factors when determining if you automatically win an encounter. Remove all your ailments first. You can win more encounters by equipping the ineffective Casey Bat.
- Bionic Krakens outside the final boss chamber drops the Gutsy Bat. If you can get them to spawn. Only worth it for completion.