Stunt Dirt Bike is a physics bike game about balance: ramps, gaps and terrain that punish the wrong angle far more than the wrong speed.
Leaning is the core control. You're constantly adjusting the bike's attitude in the air and on slopes, which is what separates a clean run from a crash on the first jump.
Level the bike before landing. The lean controls exist for exactly this, and the angle on touchdown matters far more than your speed.
Yes — hold the lean on a big jump, but only attempt one when you have enough height to complete the rotation.
Yes — a light 2D game with nothing to install.