Actually a super fun idea -- I've seen the "use your dead body" idea explored a lot in this jam, but this is the first time I've seen it applied with a physics vehicle. The overall mechanics are easy to learn and satisfying to use, but I found the general "rules" of the game inconsistent: I'd leave a "dead" car behind to use as a ramp, and sometimes it'd just despawn before I could get to it, and sometimes I'd try to leave behind wreckage and it just wouldn't. I'm not sure if this was intentional or just bugs (understandable given it was made in 72 hours), but those were some of the issues I ran into.
In the end I gave up on the third level, but I still had a good time with this game while I played. Nice work!