After reviewing the original Atari 2600 game, I think that you could make the moving "cars" using blocks. If you check the original, they have only one color per horizontal line and that is perfect for the good'n'old MSX. Using blocks you can keep smooth scrolling (redefining blocks) and have, as the original, 3 cars in a row or even the long trucks. And so you can use sprites just for the moving players and have up to 2 colors per player without any flickering.
or 4 players simultaneously if keeping 1 colour per player!
(i really enjoy a lot the idea of games for 4 players on 8 bit machines, just like what i sent to csscgc once - http://nitrofurano.altervista.org/retrocoding/zxspectrum/misc/bacaball.html
about moving "cars" as redefined blocks, it would be amazing if i could do that!
(but btw, i'll keep this idea in mind and hoping that one day i'll be able to do this
, and anyway, the sources will be released as well, for people that might want to improve it somehow! )
Anyway, thank you for proposing this game. I remember playing it with some cousing ages ago and enjoying it very much.