From Halopedia, the Halo wiki
Warthog Launch is a flash game created by Boll, a prominent member in the Halo community. Due to the popularity of the game, it was included as part of the Limited Edition and Legendary Edition of Halo 3.
The point of the game is to launch a Warthog using grenades so that it kills all the Engineers with one launch. It is a simple 2D type game and is modeled somewhat after Stunmutt's One One Se7en comics.