Disgaea 2: Cursed Memories/Town Fields

Stage 1-1: Beginner's Field
Dark Sun - 3 Difficulty
 * 1) Nothing
 * 2) Revives all fallen enemies
 * 3) (repeat)

While the Dark Sun's effect is potentially hazardous, the Sun itself only has a difficulty of three. You should be able to take it out with a single ascent sacrifice around Lv80 if they're a warrior-type. A lower level unit could also take it out with one strike if you lift them several times over. Once the main threat is gone, this map is fairly simple. There are only three enemies, positioned far from one another at distant corners of the map. Since these enemies won't approach until one of your characters enters their attack range, you can choose to only fight one or two at a time.

The monsters in this stage have rather weak weapons for their level, and they possess no forms of armor, so don't let their levels fool you into thinking they're unbeatable. You might even be able to defeat all three with characters Lv40 or lower, if you have good sets of equipment.

An Observer's DEF is usually half or less of its RES, and, as stated, these particular enemies possess no armor. Because of this, you should be better off fighting them with physical attacks instead of spells.

Stage 1-4: Dead Tree Field
Geo Symbols - Aqua panels only
 * Aqua symbol 'No Lifting' on Aqua panels
 * Aqua symbol 'Reverse Damage' on Aqua panels

Dark Sun - 10 Difficulty
 * 1) Ally Changed into Dragon
 * 2) (repeats)

How to Unlock: Kill either an enemy or ally Green Skull on the normal 1-4 stage. Transportation to the Dark World version is instantaneous.

If you have one or two Healers (or other characters with healing spells) of decent strength, this stage should be no problem for you. All eight magicians are lined up in a 2x4 pattern on the Reverse Damage Geo Panels, and will not move from their positions, so you should be able to take them all out in two Giga Heal area-of-effect spells. Try not to have your characters advance more than they must to cast their spells, as the mages could possibly survive and try to counterattack. However, they won't move from their positions by their own actions, and won't be able to hit your units if you're out of their spells' range.

If you somehow don't manage to defeat all of your enemies in the first turn, or if you only have one Healer, it probably won't hurt much to just keep her out there to endure your enemy's attacks. Healers have naturally high RES, and you've likely focused her armor to enhance RES since it's the stat used for healing spells. Add that onto the fact that all Healers have an innate ability to resist elemental attacks, and you'll know your Healer is sure to survive the magician's fire spells.

The Ally Change will only affect one of your human characters on the map, chosen at random. Since healing spells are kept with the change into monsters, there's no need to worry about Healers.