Episode I: Prince of the Netherworld
Magnificent Gate
Near the base panel are two geo symbols. One of them increases the enemy's strength and one increases the amount of experience you gain from defeating the enemies. Before destroying the Enemy Boost geo symbol, you should check the bonuses being offered for having a high combo count. If the bonuses include alot of experience or good items, you may want to put the experience geo symbol on the colored tile before destroying the Enemy Boost symbol to create a large chain. Alternatively, destroy the Enemy Boost symbol and then place the Experience symbol on the colored tiles to increase the experience gained from defeating the enemies.
Once the Enemy Boost symbol is out of the way, you should have no problem defeating the foes.
Blessed Court
Corridor of Love
Hall of Caresses
Episode II: Enter Flonne
Forsaken Land
Icy Breath
Eternal Winter
White Death
Episode III: A Hint of Kindness
Gaudy Entrance
Golden Courtyard
Flashy Passage
Lavish Hall
Episode IV: Gift From an Angel
Road of Flames
Parched Ground
Blazing Field
Molten Labyrinth
Episode V: Etna's Secret
Absolute Zero
Endless White
Terrible Cold
Ice Queen
Episode VI: Laharl's Challenge
Calamity Forest
Ritual Site
Witches' Den
Writing Shadow
Nightdwellers
Heart of Evil
Episode VII: On Being an Overlord
Scorching Wind
Column of Fire
Raging Earth
Crimson Plains
Ember of Dreams
Episode VIII: Reincarnation
Theatre of Death
Frigid Garden
Freezing Souls
Under the Moon
Episode IX: Captain Gordon, Defender of Earth
Valgipus IV
Thurvean Sector
Sphere VIII
Cross-Point
Primordial Soup
Episode X: Angels, Demons, and Humans
Fervent Melody
Wasteland of Woe
River of Lava
Searing Tyranny
Inferno
Episode XI: Hero's Will, Overlord's Way
Ghostly Whisper
Rising Fear
Crawling Terror
Hero's Tomb
Episode XII: War of the Netherworld, Part 1
Embryon
Core Point No. 4
Star Cluster
Sidereal Rift
Episode XIII: War of the Netherworld, Part 2
Point Alpha-III
Main Corridor 1
Main Corridor 2
Main Corridor 3
Bridge
Episode XIV: What Lies Beyond the Battle
Field of Virtue
Paradise
Angelic Choir
Coliseum
Divine Prison
Inner Sanctum
Hall of Justice
Sacred Alter