Disgaea DS/New features
Disgaea DS includes not only the original content of Disgaea: Hour of Darkness, but the extra content from Disgaea: Afternoon of Darkness as well. The DS controls allow for camera control (zooming, rotation, etc.), unit and menu selection, and movement using the . However, most of the controls are still available through the remainder of the buttons. See Controls for more detailed information.
This version of the game also includes a map view for the upper screen of the DS. While the upper screen is used through most of the game to make better presentation of the data on the handheld's screen real estate. In battle it becomes a top-down view of the field with information detailing the location of units in the battle (both friendly and enemy), the base panel, geo panels, and further information about specific squares. Geo Symbols appear as they would if viewed from the top-down angle, in their individual colors. The cursor location is also displayed for reference, and to make it easier to correlate what you are seeing on one screen with the other.
Units are displayed as arrow-like icons indicating the direction they are facing (blue/green for friendly, red for enemies). A unit's icon will become darker in color when they have completed their turn, making it easy to see in a glance if you can bring other characters in the area into position. Further, the map screen will display the area of a skill effect, often making it much clearer whether or not a particular attack will hit a particular enemy, or which allies may be impacted by a unit's actions. Where the 3D view is sometimes found to be obtrusive in all three versions of the game, the DS' upper screen often makes things clear.
 Audio differences
This is the first Disgaea game released in the US to not include the original Japanese audio. In addition, much of the English audio has been removed. Almost any English audio that was accompanied by English text containing the same lines was removed, which means that most of the cut-scenes contain the soundtrack, sound effects, and the text for the characters' lines, but not the audio for the lines themselves.
 Prinny commentary, dood!
On a New Game+, this version of the game will give a running commentary from a Prinny. The commentary will only appear on the top screen during existing cut-scenes, so it won't interrupt gameplay. It offers a new approach to a story that you may have already played a few times. The commentary can be removed in the game's Settings menu, and is only available in a New Game+ game.
Note that the Prinny commentary will not appear in a normal game even if the option is enabled in the Settings menu and another save exists with the feature unlocked and enabled. It only appears in a game started with the New Game+ option in the main menu.
 New playable character
Spoiler warning! This section of the article contains spoilers, or hints about the game's storyline or progression.
You might want to skip down to the next heading if you do not want facts about the game's storyline or plot revealed to you.
Disgaea DS also adds a new playable character, Pleinar. In order to unlock this character, you simply need to start the game from a New Game+ (see the previous section's sidebar for the fastest way to get a New Game+). At this point you'll have to unlock the Dark Assembly, which means getting through the first tutorial (in the normal game) or the first mission (in Etna Mode).
Once the first tutorial (or mission) is complete, talk to Pleinar (the person that you would normally talk to in order to visit the Dark Assembly). An empty space will appear in the menu. Select that space, and with a little persuasion, she'll join the group. She'll have a gun and an Imperial Seal, which make for a nice start. Give her some shoes and glasses, maybe a better gun, and she'll be ready to do some damage in no time. Using a gun means that she'll take advantage of her high HIT stat, even when using her unique skill, Dropping Usagi, which otherwise utilizes her (much weaker) ATK stat to determine damage.
Transmigrating Pleinair involves significant extra cost versus transmigrating other characters. It shouldn't be enough to stop you from doing so when the time comes, but it's something to consider anyway.