I have all the leaks and some dude on Reddit fully analyzed them all.
This game is going to be impressive. And the leaks werent even 30% of the game.
Btw, they came out of QA. These videos were recorded to demonstrate test cases either passing or failing, by QA engineers who were mainly running engine tests. These were taken recently - all the way up to the leak itself, basically
A lot of the mechanics under test are basic ones. There's a fake map area with graded ramps for different vehicles. In some places, arguably, there's some map testing going on (but mostly ramp related stuff). A lot of these basics need to be pretty locked down early in development ‘cause they influence everything: if you make vehicles launch faster off ramps by changing the physics late in the day, you then have to go through the map and adjust every ramp you built.