There weren't many 'full games' available for the DSi to begin with but one which did manage to make it on to the download service during the launch window was Virtual Playground's Oscar in Toyland. If you did enjoy this 'old school' platformer you'll be pleased to learn that Oscar is at it again and there's a dedicated website where you can read all about it and view footage of the game in action.

Following his mega successful Oscar in Toyland escapades, Oscar now plays the leading actor in sensational worlds of hit movies and TV shows. From Sci Fi to Cartoon, Western to War, Horror to Jurassic and zany Game show host, this is a game not to be missed.
Oscar in Movieland pushes the DSiWare to NEW limits with EYE POPPING graphics, PARALLAX scrolling backgrounds and FABULOUS gameplay.

This jump and run game is EASY to play, packed with hours of fun and non-stop ACTION.
Use Wings to Fly, Springy Boots to Jump and Oscar's secret weapon - his magical Yo-Yo to swing on and zap enemies in some of the 
craziest platform levels you'll ever play.

You can get to the site now by clicking here.