Source - http://www.gamasutra.com/blogs/JoshB...ame_Design.php

Recently, Kotaku published a major exposé regarding the six-plus years of development on BioWare’s Anthem. One of the industry’s most celebrated studios has now published two critical failures (the other being Mass Effect Andromeda). There were many issues uncovered in Kotaku’s piece, but from a game design perspective, one of them stands out above all others—not figuring out what your game is about.

(The following discussion was written for the online magazine Super Jump Magazine and I'm posting a snippet of it here that relates to design. You can reach the whole article here)

Core gameplay loop

In game design terms, the core gameplay loop (or CGL for this piece) is the primary game system or mechanic that defines your title. This is what you build your entire game around, and it’s often the qualifier that determines what genre your game belongs to.
While this may sound simple from the outside, many developers large and small have failed because they couldn’t figure this out.
From the indie side, we often see developers focus on one cool mechanic or game system, but they struggle to figure out how to turn that into a game. This can lead to titles that quickly wear out their welcome. On the other hand, we see developers that forget—or unable to settle on—their core gameplay loop, and try to fit as many game systems as they can into the title. The “kitchen sink approach” may lead to a large game, but it’s often one that feels more like a Frankenstein’s monster than a completed game design.
The challenge when discussing the CGL is that it’s not something consumers—and sometimes even developers—identify as the main problem. Often, people will fixate on more specific issues (like technical problems), specific quality of life issues, or simply a game not being finished—all without understanding the root cause. As a consumer, you’re generally only seeing the final product and, by definition, you’re not seeing the many hours of struggle involved in developing the game.
In order to know how I came to this perspective, I want to share with you a tale of a studio that chased their CGL for over for years and, in the process, they ended up closing down.

Clockwork failure

You may or may not have heard of the studio Gaslamp Games. They were an indie developer who earned a lot of fans for their hit rogue-like Dungeons of Dredmor. Following the success, they went all-in with the game Clockwork Empires—a 3D dwarf fortress-like with steampunk and Lovecraftian elements.
Their first description of the game instantly made me fall in love with it, and I played it on and off for the years it was on early access. The problem Gaslamp Games had with Clockwork Empires was that they never figured out how they wanted their CGL to develop. They had multiple systems for civilians, buildings, and progress, but none of it was coalescing into a defined game.
Was the game supposed to be about dealing with your people, or was it a resource management game built on busywork? There were many months when they would redo game systems and try something else, to then change them a few months later. The Lovecraftian elements that were supposed to be integrated into the city management system never materialized.
By the end of the early access period, they were finally starting to show some concrete process, but they ran out of money and were forced to release the game unfinished. Following the release, the studio was shut down.
The fate of Clockwork Empires is the perfect example of how not figuring out your CGL escalates fast.

How problems escalate

Video game creation is an iterative process, and no designer knows exactly how a game is going to turn out on day one. However, the CGL is your foundation and blueprint going forward when building a game, and when you don’t understand what that is, it can lead to massive problems.
Without knowing your CGL, you’re not going to be able to answer the question: “What is my game about?” That means you’re going to need to spend time making different versions of your game with various CGLs. For each build or system you throw out, that’s time and money you will never get back. Any additional work you do on your game while still figuring out the CGL is at risk of being thrown out as well.

This can lead to management problems; especially at larger studios with departments of people working on a single game. If you don’t have a key vision for how your game works, how are you supposed to manage people to build the game?

Another point is that without being able to settle on a CGL, it leaves your game susceptible to scope creep. The ever popular phrase of “let’s just add X because it worked in this game,” can easily overwhelm a team.
When a game goes wrong, it can look like a mismanaged mess, but when it goes right, it can seem almost like the game had no problems.
Being able to take a step back and say that a game is not working is just as important as doing what you can to try to make something work. But when all things are said and done, if you can’t answer what your game is after working on it for more than a year—let alone six—then it’s time to pull the plug.