The MSX conversion of Costa Panayi‘s Highway Encounter was coded by Pedro Sudon in 1985. It is possible that the game was only ever published in Spain on the MSX since the only versions I can find are in Spanish.
Highway Encounter on the MSX is pretty much identical to the original ZX Spectrum version, and it looks beautiful and crisp, over its 30 different isometric levels.
Just like the ZX Spectrum version: you control a robot, called a Vorton, leading a line of other Vortons who are pushing a bomb up a road infested by hostile aliens and littered with barrels and hazards. Your Vorton can rotate in eight directions, move forward, and shoot a bolt of energy out of its head. The energy bolt will move barrels and destroy an alien if shot, but the Vorton can also be destroyed by being touched by an alien, or by moving into a deadly hazard.
If you lose the lead Vorton it is replaced by the next Vorton in line, until you have no Vortons left. So what you’re basically doing is clearing the way so that you can make it as far up the road as possible, with the ultimate aim being to deposit the bomb on a target tile on screen zero. If you reach the end of the road (literally, not metaphorically) you then get the honour of destroying the enemy mothership – that is: if you managed to get the bomb all the way to the end.
Just like the Spectrum version, this MSX conversion does suffer a little from slowdown when there are a lot of moving objects on-screen at the same time, but the gameplay overall is pretty faultless. Highway Encounter is an interesting, simple and challenging game that has stood the test of time well.