Here is the full list of all 100 Picayune Dreams achievements.
Complete Weapon collection.
Upgrade the Wicked Walkman to Level 8.
Upgrade the Electric Eel to Level 8.
Upgrade the Hydrocillator to Level 8.
Upgrade the Halo to Level 8.
Upgrade the Demon Wings to Level 8.
Upgrade the Frosty Cone to Level 8.
Beat Overdrive 5.
Complete Enemy collection.
Kill 1,000,000 enemies.
Upgrade the IV Bag to Level 8.
Upgrade the Pleonexic Crown to Level 8.
Upgrade the Legsaw to Level 8.
Upgrade the Plasma Lamp to Level 8.
Upgrade the Fire Lighter to Level 8.
Upgrade the Shrapnel Shells to Level 8.
Upgrade the Ultrabuster to Level 8.
Beat Overdrive 4.
Kill 500,000 enemies.
Upgrade 1000 times.
Reach 40 Mortality.
Reach 50 Mortality.
Upgrade the Frost Globe to Level 8.
Upgrade the Soul Spear to Level 8.
Upgrade the Volatile C4 to Level 8.
Beat a run with 200%+ Pickup Size.
Beat a run with 10+ Blackhole Slots.
Beat Overdrive 3.
Beat a run without upgrading CORE.
Defeat Yuki.
See the true ending.
Find 10 Drills.
Upgrade the Eye2 to Level 8.
Upgrade the Energizing Battery to Level 8.
Upgrade the Mask of Plague to Level 8.
Upgrade the Shinobi Equipment to Level 8.
Upgrade the Flame Thrower to Level 8.
Upgrade the Strike Call to Level 8.
Upgrade the Digiwatch to Level 8.
Upgrade the Overcharged Engine to Level 8.
Beat Overdrive 2.
Beat a run without using auto-aim.
Beat a run with 200%+ Vitality.
Beat a run with 200%+ Projectile Speed.
Kill 100,000 enemies.
Kill 25 Bosses.
Upgrade 500 times.
Reach 30 Mortality.
Reach Skill Level 20.
Upgrade the CORE to Level 8.
Upgrade the Injection to Level 8.
Upgrade the Hunter's Bow to Level 8.
Upgrade the Telecom to Level 8.
Reach Skill Level 25.
Beat a run with 200%+ Velocity.
Beat Overdrive 1.
Beat a run with 200%+ Attack Size.
Upgrade the Horns to Level 8.
See all of the memories.
Kill 50,000 enemies.
Reach Skill Level 15.
Upgrade the Static Satellite to Level 8.
Upgrade the Angel Wings to Level 8.
Beat the game.
Beat a run without using Halos or IVBags.
Defeat the Demon.
Defeat Picayune.
Kill 25,000 enemies.
Find 10 Chain Grenades.
Find 10 Floppies.
Upgrade the Missile Pack to Level 8.
Upgrade the Parasight to Level 8.
Defeat the Ghost.
Reach Skill Level 10.
Upgrade the Dagger Glove to Level 8.
Upgrade the Slime Spike to Level 8.
Defeat the Biker
Kill 10,000 enemies.
Upgrade 100 times.
Upgrade the Chainbelt to Level 8.
Find 10 Blackholes.
Find 10 Magnets.
Find 10 HP Vials.
Reach Skill Level 5.
Die.
Defeat the Worm.
Defeat the Bunny.
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Beat the game with Slime Spike, Chainbelt, LegSaw and Hydrocillator.
Beat the game with Core, UltraBuster, Eye2 and Hunter's Bow.
Enable Debug Mode.
Find 10 Dice.
RIP.
Upgrade the Yoyo Rack to Level 8.
Upgrade the Defense Turret to Level 8.
Upgrade the Element Crystal to Level 8.
Beat a Daily.
I brought you a head.
Kill the Worm without splitting it.
Beat the game without being hit by an enemy or boss or bullet.