Sandbox Engine DS-DSi is a 3D FPS style DSi hybrid (for DSi only but also playable on DS) game which started back in 2010 on the DS but when the DSi sudokuhax was discovered its being made with DSi mode in mind.

Release notes:

I added lots more in this version.

+ Made lots of changes to the code, & bug fixes.
+ Actually added a basic GUI finally.
+ There are 4 maps now, I’m adding more objects, cars, buildings, houses & maps, etc & looking for ways to make the maps bigger.
+ The texture changing & ability to move the camera up & down has been removed in this release but will return next release. (Edit: I saved the ability to pan camera up & down in this version)
+ I made some textures higher resolution like grass, & snow. More will have higher resolution in next version.

The 1st map a small island with a house, the 2nd map a sandy beach, the 3rd map is just a small snowy island but there’s a building with floors, & the 4th map is like an intersection, with some houses & the building & cars.

http://gbatemp.net/t292050-t3-games-official-update-thread