The European version was retitled Super Probotector - Alien Rebels and the protagonists were replaced with humanoid robots. This change followed suit with the first Contra game released in 1990 for the NES, which was renamed Probotector in Europe and also featured robotic characters and enemies (probably due to some form of censorship).
There are a couple of other notable differences between the original Japanese version and the other releases that are worth noting. First off, Contra Spirits gives players infinite continues, whereas the other releases award the player with a limited amount at the beginning of the game. Then, the Japanese version surprisingly features a couple of cheat codes that were completely omitted from the other releases (such as 'stage select' and 'sound test').
An European Sample cartridge is known to exists.
November 1992 - Consoles+ No. 14: 88/100