Hotel Dusk sucks ass. WHat the hell are you trying to do to him, dude? Torture him?
Good ds games:
Etrian Odyssey - dungeon crawlin', map makin', hardcore rpg fun
Phoenix Wright - decent adventure game series, it's an interesting court "sim" take on the adventure genre. scramble for clues to save your clients from impending doom.
Kirby Canvas Curse (if you can find it) - excellent platformer, one of the most unique on the system. You platform with the styles, and it's anything BUT gimmicky. You use the stylus to draw lines to keep Kirby from harms way. Best platformer in ages.
Elite Beat Agents - Rhythm game that's a blast to play
Shiren the Wanderer - I haven't played this, but a lot of folks say it's amazing. It's another ds dungeon crawler. Hard as balls apparently. Sounds like my type of thing.
Those should start you out well.