Rayman DS is a port of the Nintendo 64 version of Rayman 2: The Great Escape, released as one of the launch titles for the DS. Unlike most versions of Rayman 2, which are critically acclaimed, the DS port is unfortunately plagued by a myriad of technical issues.
Why It Sucks
Minor false advertising: This is a port of Rayman 2, yet Rayman's modern design (from Rayman 3 and onwards) is used on the front of the cover.
It doesn't offer anything new to the table aside from the new touch controls.
As stated above, there are multiple technical issues, with two examples being the encounter with Umber and in the flower ride in the Sanctuary of Rock and Lava, where Rayman can slip off, even during Umber's cinematic, and the giant spider at the beginning of the Tomb of the Ancients will disappear a few seconds after the cutscene in which it first appears.
The graphics aren't touched up on, which makes the game appear dated.
The textures are much more jagged due to the DS lacking a texture filtering system (the textures themselves are unchanged, however).
You can only change Rayman's speed by using the touch screen controls.
The Only Redeeming Quality
For what it's worth, the port is still very playable in spite of the technical difficulties.