The 22-year-old anchorman spent three days training with Ronny Deila’s squad before flying home at the weekend.
Crepulja’s contract expires in June and his top-flight club Slaven Belupo have indicated they will accept a cut-price £300,000 bid for the former Under-20 international.
He admitted: “I cannot tell any details about my future. For such information, you would have to ask Celtic.
“But it is heaven on earth, you really cannot compare it to here – it’s another world. For me, it was a fantastic experience to be part of Celtic, even if it was just for a few days.
“Celtic is a big, well-known European club. Going into their ranks would be great. But, as I say, I am not allowed to reveal the details.”
Crepulja arrived in time to watch the Hoops hammer Hamilton 8-1 at Parkhead on Tuesday night and was clearly impressed by their display of the players and the backing from the fans..
He added: “It’s impossible to describe. The stadium holds 60,000 spectators and at the match there were about 45,000 fans. And they were always giving their support, greeting and cheering their team.
“It’s a pleasure, something completely different from what it is like here.
“There is no big difference in training. They do a lot with the ball like we do in Croatia. And a lot of the time is spent on technique and tactics.”
“The players are all big names, players who know the English Premier League and are on television.
“I would like to thank Jozo Simunovic who was a real host in Glasgow. He greeted me, we met everyone at the club and we hung out every day.”
Gaffer Deila wanted to add a few days to Crepulja’s trial period, but it was blocked by his club.
Director Zvonimir Simunovic – no relation to the Hoops’ summer buy from Dinamo Zagreb – said: “Celtic asked us to extend his stay because the manager needs more time, but we couldn’t agree.
“Lujban is our most important player.”