I'm unable to find a great deal of information on this version currently. I have to assume its an 'unofficial' version however but its quite remarkable to fit a smaller version of this game into 16K. Author is listed as Ales Martinik.
Being a ZX81 game there's no colour and no sound.
I'm unable to find an English version of it currently either. I'm unsure if there are more than the eleven levels indicated in the 'demo mode'. Here are a few screenshots for the moment:
In Game Screenshots: