So apparently four elements trainer was in development hell from that definition. Or Undertale also.
Turns out if you want to have good writing and/or good art it takes time.
For example the first Harry Potter novel took 6 years to write.
Development hell does not always mean the thing being produced won't ever be completed. (That's something entirely different called "Vapor Ware") Rather that it is taking far longer than what the average time to completion for a similar product should take. A good example of this, would be Star Citizen... which is pushing 10 years of development with no real progress on many of, if not most of the promised features or promised starships. Another great example is the game "Duke Nukem Forever." That game was stuck in a development hell that not only saw the company producing it completely shutting down and getting bought, but also took 14 years to finally produce. When it did finally release, unfortunately, it was garbage.
Whatever the case, "Development hell" simply means something is taking, on average, longer than it should take under reasonable circumstances.
For an indie game of any genre, the average time to completion is at most two years. They
need the game released in that time frame or they are going to make a loss due to changes in technology, player interest, and hype for the game. The longer it takes for production to complete, regardless of the reason, the more it counts against the indie game developer.