Here is my record of Kickstarter failures/challenges:
HEX MMO Trading Card Game - Digitial M:tG from Cryptozoic that took advantage of being digital to do things you can't do with physical cards. I was able to play about 400 hours of it, but they never delivered most of what was promised. They stopped supporting it a few years ago, meaning my entire investmet is gone except for the pleasure of opening packs and playing a lot of early sealed deck. I'd have been better off buying M:tG cards.
Map Flats - Vinyl tabletop RPG Maps - They promosed double sided high quality Vinyl Maps. In the end, I received single sided maps and the quality was mediocre. I still use them, but far from what was promised.
KINGDOM BUILDER - I backed for Harvest and Marshlands. Queen Games lied, and then put the games on shelves before delivering to backers. When they delivered, they gave many backers things they did not pay for, making those that paid for those things frustrated that they were charged for something Queen gave to others (which is a bit petty of a complaint, but still left a lot of people with a bad taste in their mouth). They clearly think their customers are unimportant and dumb based upon how they treat the customers. I like their games from a design perspective, but I won't buy from them on KS, or in stores, again. Only in the secondary market (as a used game). They were horrible.
Modular Underground Project - 3D Dungeon Wargame Terrain - Also known as Oblivion, this project was a real cluster but they're slowly trying to make it right. Slowly. This plastic RPG terrain was to be delivered in October 2017 and many people have yet to see anything delivered, while others, like myself have seen piecemeal delivery. At this point, all I really need are some Wooden Floors to be delivered as there are a lot of pieces I have that are supposed to attach to those Wooden Floors. The company has posted a lot of statements about how they'll make this right only to fail to deliver on those promises time and again ... and then surprisingly take a positive step to deliver on some part of the promises out of the blue. The method of 'keeping hope alive but never quite delivering fully' has been kind of like 5 years of nails on a chalkboard.
DEEP MADNESS / Dawn of Madness - Incredibly slow in delivery. I've backed a few of the projects they've made, but they have all been ridiculously slow to deliver.
Iconic Mythical Collection RPG Dice Sets by Kraken Dice - This company advertised crisp and clear transparent dice with cool designs in the center. What was delivered looked cloudy and worse than the dice in the $0.25 bin at the FLGS. Clear lies and misrepresentation and a company I will never trust again.
Blacklist Miniatures: Fantasy Series 1 - These were cheap plastic miniatures that cover a spectrum of traditional D&D monsters. I told a lot of my friends about them and recommended they back to get a great 'starter set' of unpainted minis for their young kids. They delivered internationally last year, about a year late, but domestic delivered have been help up in a warehouse here in the US since December. The reasons are a little unclear, but appear to be that they don't have the money to pay to have them delivered, and are getting in deeper water due to storage costs. The worse part is that the company has lied to backers over and over and over and over and over throughout the campaign. I am also a backer for their second KS of Fantasy Miniatures that were supposed to be delivered this month originally, but last report claimed we'd get them in August. Given that the minis are here in the US, I do expect to get them ... but the wait has been ridiculous.
Stairslide: Indoor Slide For Stairs - These recklessly fun slides that go on your indoor stairs ticked me off by changing their specifications after we backed, changing the number of slides you'd need to cover a given distance of stairs. Still, my kids love the things and nobody has lost a finger, yet.
Various CMON - They have done nothing wrong, per se, even delivering early on some pledges, but they have released an insane amount of stuff and the prices are skyrocketing. I backed them for Blood Rage, Rising Sun, Ankh, Cthulhu: Death May Die, Hate, Rise of Moloch, Marvel United, Marvel United: X-Men, Zombidice: Undead or Alive and Marvel Zombies. The cost of their KS offerings have risen and risen and risen and risen ... to the point where they're manipulative. They use 'Fear of Missing Out' to get people to spend several hundred dollars (over $500 these days) on their KS offerings. I really hope they start to revisit some of their earlier models and release quality games at a much lower price point with fewer expansions.
There are dozens of other KS that have delivered late, but I consider that a normal risk so long as the delivery is not more than 100% late.