Rocket League cars flip, spin and fly, and still come down on their wheels. Real car physics would fight them: in Psyonix's own GDC talk (2018), Jared Cone shows a car that lands on its side, "takes a while to recover" and ends up "facing the wrong direction". So Rocket League adds forces no real car has. When the car touches the ground, wheel or body, a rolling torque turns its roof away from the ground. Once a wheel is down, "a downward linear force" clamps it to the ground. With three or more wheels down, both switch off. Even the suspension? In his words, "it's all fake, it's all just done in the animation system."

A game car doesn't land on its wheels. The game puts it there.

The stadium, the cars and the landing sim in this film are our own simplified version, built in code; the game's drop is shown slowed down, then at full speed.

Which game's hidden trick should we cut open next?

Sources: Jared Cone (Psyonix), "It IS Rocket Science! The Physics of Rocket League Detailed", GDC 2018.
Unofficial. Not affiliated with or endorsed by Psyonix or Epic Games.
Sounds and music: our own, made in code.