first of all, the soundtrack is top notch! is there a place i can find more of this person's music?
the idea of your attacks being able to kill you on subsequent laps is good game design! it has risk/reward baked into it. i do think, with some improvements, the game could be a lot more fun.
im guessing the ultimate goal of the game is to kill all the other cars. for context, i love "masocore" games like Getting Over It, etc (though I dislike the "masocore"/"rage games" genre label because they make it sound like the player is in pain, rather than just someone who enjoys getting better at a game for real instead of the game getting easier for them via leveling or whatever). on paper the fact that one mistake starts the game all over doesn't bother me. but i didn't have the patience to beat the forest track for several reasons.
it'd be nice to have some indicator of actual progress towards success (some UI saying "3/12 cars killed" or something, for example). without it, it's hard to gauge the success level of a run, and i'm not even sure if what i'm doing will actually lead to success.
a lot of time is spent just on straight shots of road, which feels a bit slow. it'd be nice if there was a way to speed up, and a reward for taking the risk of going faster, like the game keeping track of your completion time. maybe it does, but if that's something the player should strive for, it should probably be onscreen somewhere.
the controls feel a bit delayed, but i can see why they were necessary to make the act of putting oil in front of an enemy car more challenging and rewarding. one thing i questioned was the braking cooldown. i'm sure you added it for a reason though. if so there should at least be more feedback since it's a bit nonstandard, usually i'd expect to be able to tap brake to go just a little bit slower.
i did love the design and the overall vibe so i think with those little tweaks the game could be great!