Impossible Mission is a pretty good old school game, featuring the original, remake and all new modes. Not a run and shooter but its one of those "one hit and you're dead" sort of games.
Geometry Wars: Galaxies is a great old school arcade shooter.
Konami's Arcade Classics has many arcade titles on it.
Orcs & Elves is a pretty good old school RPG/dungeon crawler like we had in the EGA PC days.
Also theres Arkanoid DS, Ultimate Mortal Kombat & Worms: Open Warfare 2. Theres also New Zealand Story but its best to try it on a emulator as the DS version has some horrid mini games.
But its best to check out the emulation side of things, Mega Drive/Genesis, NES, GB, MAME (the 80's games) are pretty solid on the emulation side of things. SNES ain't too bad but a lot of stuff won't work.
Coming soon theres Legend of Kage 2, Space Invaders Extreme, Metal Slug 7, 07 Commando and Bangai-O Spirits that will keep the retro gamers happy in '08.