A slew of scathing reviews have been left on The Sun Slider Facebook page, complaining about lengthy queues, a lack of changing facilities and lockers, and most importantly the low water pressure which has reportedly blighted the main attraction.
The highlight of today's Sheffield Slip and Slide Fest was billed as a 1,000ft-long three-lane inflatable water slide, and visitors were also promised foam cannons, water soakers and much more.
But, despite photos showing some children using the slide, the festival appears to have fallen short of many people's expectations.
Andrew Fox, from Loxley, said he and his partner arrived at 10am with their 12-year-old daughter Nicole and one of her friends, who were really excited about the water slide, but they left disappointed three hours later having been unable to use the slide once.
"I just thought it was farce, to be honest. There was a complete lack of organisation," he said.
"I appreciate things can go wrong unexpectedly but they should at least have kept people informed about what they were doing.
"There were hundreds of kids queuing up for hours and the organisers were chucking small amounts of water down the slide which you could see after 10 seconds wasn't going to be enough.
"They kept saying it would be resolved soon but didn't say what they were doing to resolve it."
Dan Wall, who went with his wife and two children, aged 10 and seven, said: "When we got there we were told the event was delayed because there was no water pressure.
"There should have been three lanes but they actually had one and then none because they were waiting for more water.
"We paid Â£10 for a ticket through Groupon but there were people there who'd paid Â£50 a ticket, including a goody bag, and the person next to us in the queue had travelled all the way from Grimsby.
"It was so disappointing. It was a farce."
Some people also raised concerns about safety at the event, claiming children had injured themselves attempting to use the slide and the bouncy castle had deflated with children on it.
Yorkshire Ambulance Service has yet to respond to an enquiry by The Star to confirm whether paramedics were called on to treat anybody.
Writing on the organisers' Facebook page, Natalie Turner said: "Complete disaster, no changing facilities, no foam cannon, no mist cannon, no small slide, no water. NO SLIDE and no regard for safety.
"My kids queued for three hours got shouted at and pushed by event staff. One them eventually got to go down an almost dry slide the other was too upset. I will be expecting a full refund as I paid for something I didn't get. DISGUSTED."
Kimberley White, who left the minimum one-star review on Facebook, wrote: "Appalling how this has been organised. Not set up on time and then over an hour after it should have started realised there isn't enough water pressure!
"No water cannons, mist or foam. No changing facilities, no lockers. No water slides for under-sixes as stated. Kids jumping on wherever as the queue is so big. Unsafe as kids are running as they can't slide. Two hours after it should have started they let a few down with a trickle of water for it to deflate! Just unbelievable."
Organisers had said part of all ticket sales would be donated to Bluebell Wood Children's Hospice.
The Star has contacted the event's organisers, who have yet to respond.