Not sure if it was on purpose but these colors remind me of Color Infrared film (EIR) I used to shoot. It is very expensive. I remember back in 1999, I could shoot and process 2 rolls of EIR for about $100.
In the photographer's words:
"the second shot overexposed the film except in the black ball where i appears with friends...lucky ahah:)"
What he is saying is that the ball area was black meaning that part of the film was not exposed. Then he luckily put the group of people in that same unexposed film part so the people came out clear. Because the area surrounding the people was exposed properly and with the second exposure it is now overexposed which in this case is fantastic. Lovely detail in the overexposed areas.
BTW, in order to do multiple exposures you need a camera that allows you to manually make that decision.
Taken by jeabzz with a Lomo LC-A Nikon Fm 2 loaded with Fuji Velvia 100F film in Paris, France.