Silent Scope
Silent Scope is a Konami-made on-rails light gun shooter ported from the arcade to the Dreamcast in 2000. It's silly and fun, and kind of tricky.
Confidential Mission
One of the last official games released on the SEGA Dreamcast, Confidential Mission is a strong port of a decent (if a bit forgettable) light gun game.
The House of the Dead 2
The Dreamcast port of The House of the Dead 2 is one of the best (and spooookiest) light fun shooters ever made!
The Typing of the Dead
The quirky and hilarious typing training game based on SEGA’s The House of the Dead 2 received a Dreamcast port in 2000, and it’s since become a cult classic.