Dragon's Curse: get Mouse Man. Stock up on ammo, make sure to have boomerangs. Sneak into Tiger Man stage. Kill boss by jumping and shooting all ammo first, then recycle boomerangs till he's dead. You'll morph into Bird Man and all forms will be available.
Shapeshifter: get Shadowcat form. Kill dinos for diamonds. Morph jump through underground Phoenix stage to get key to final area. Skip 90% of the game.
Dragon Slayer: kill apes for coma darts. Make sure level up stats are set to auto. Park party in high traffic area with turbo switches on (die + elastic works best). Go to sleep. Next day party will be leveled and rich. Repeat and buy Gold Rods as you can afford them and level even faster. Game has secret "luck" limit. After a certain point instant kills will no longer work.
Blood Gear: game is non-linear. I could get past a dungeon with a locked door, so I rocket jump thrustered over the top wall of the tower and continued on. Not sure if that variant even meant for me to go through that path.
Legend of Xanadu I & II: level armor fast by only equipping one piece and letting enemies hit you.
Ys III: stand in ice tunnel where enemies fly over. Strap dice to up on dpad and turbo attack button to max your level without playing.
Order of the Griffon: When creating your party, add a fighter to one of the empty slots, then remove him and put a magic-user there. They will magically be equipped with whatever armor the fighter was wearing. As long as you don't un-equip it, they'll keep it on during the game, making them much hardier.
Ys Book I&II: Not much a secret, but I like to jumpstart Ys Book I by leaving Minea and getting the Golden Vase from the pond completely unarmed. Get it, sell it, buy ring, get reward, and skip the weakest arms and armor.
Credit forum members: Black Tiger, ROFLMAO, and Vestcoat for this week's tips and tricks!!