The other problem would be adequate funding for proper development, but today that may be dealt with by using a kickStarter or other crowdfunding method. Now for something almost every developer gets wrong, the Questing system, which is normally what you do to competently progress through the story, or the game in the general. The mistake most developers make, is that Questing is made tedious, and not all that interesting. Having a more dynamic Questing system usually helps, similar to that in Guild Wars 2.

Another problem is finding the proper demographic for your particular project. The people you want playing your game. Which means you have to be as clear as possible, as to what kind of game you want to get out into the world.

The art-style/graphics is another important thing that can easily make or break a game for certain people. The art-style is important to convey your message to the types of people and even the ages of the demographic you are trying to target.

One other problem is the Pay to Win method utilized. A sort of method where you would have micro-transactions that could affect your gameplay in such a way that gives an unfair advantage. To be honest the concept of Pay to Win is very subjective. Very few people like it, and in fact most dislike it, and certainly there are some people who are indifferent to the subject.

A cluttered and unmanageable interface is a small problem, but a problem none the less. So keep your game clean and clutter free. One more thing, so I don't find myself rambling on and on about this. The overall quality, or presentation of the game is a most important element for the developer to keep in mind at all times.

As a game developer you must listen to your community to create a good game.

I'm merely outlining what some of the issues digital games may have, and what it might take to make a good one. I am not really a pro here, I am just offering an opinion on the matter.