Bad Piggies Tusk ‘Til Dawn Level 5-21 can be 3-starred using two runs. First, just let the piggy fall through the level without any contraption. This isn’t fast enough to beat the clock, however. So to beat the intimidating 4-second threshold, quickly fire the grappling hook before the pig and box settle. This will aim it just slightly more rightward than otherwise, allowing better speed.
If you have a different strategy for completing this level feel free to leave a comment below.