Have you ever played a game’s sequel and thought it looked like a glorified DLC? It’s easy to focus so much on what is similar about two games that we completely lose the focus of what is truly different between. Sometimes, these differences are their heart and soul.

To understand what sets them apart, we have to look at their underlying mechanics and design. The first two Doom games are a great example of how two different design philosophies can create very different products even if their gameplay is quite similar.

Doom was one of the most mind-blowing games of the 90s and it’s considered the father of the First Person Shooter (FPS) genre as we know it. Sure, you can call Wolfenstein 3D, its predecessor, the grandfather of the genre if you want, but Doom is certainly more influential and it has spawned countless “Doom clones”.

What was Doom all about?

Let’s pretend you lived in a cave for the last 30 years or that you are 10 years old. Doom could be described as an FPS in which you blow demons up. It had quite a stunning 3D visual back then and a vast range of different weapons that could be used.

While the carnage is its coolest selling point, Doom is all about movement and evasion. The enemies’ hitboxes are pretty easy to hit and there is no distinction between aiming high or low so you’ll hit your targets even if you don’t aim well. The main challenge comes from movement, as you have to avoid taking too much damage while shooting. The secret for playing well is less about aiming and more about dodging long enough to survive.

Doom 1 and 2 are, in fact, quite similar in how you can play them because of this core mechanic. Doom 2’s only obvious mechanical additions are a new Shotgun and about a dozen new enemies. Someone could easily look at these two products and see only a slight improvement. However, the truth is that their level design is completely distinct.

The Level Design Of Doom

The original Doom was all about atmosphere and realism. While it may sound silly to call something like Doom realistic today, the levels looked like real places, especially in the first chapter, which was set on space bases on Mars.

One of the most interesting aspects of the three chapters of Doom 1 was how the world slowly turned into something horrific and unreal. You were a marine on Mars trying to escape during a demonic invasion that wiped out all the other humans on the planet. The story was very thin, but the environmental storytelling helped to show the stakes getting higher.

The first chapter was set in bases that featured labs, stations and military installations. The second one was in a world that was starting to get corrupted by Hell, so it mixed these locations with hellish elements. The idea that Hell was slowly taking over was very gripping and it helped to create momentum and to tell the story. In the end, you entered the actual Hell and then all hell breaks loose. Areas are more open and you can see hellfire everywhere.

There is a strong sense of progression and story in creating levels like this. There was even a map that showed your progress between the levels, a featured abandoned in the sequel.

Doom 2, on the other hand, was very similar in gameplay and yet a lot more abstract in design. The game was full of mazes. While some levels looked a lot like real places, most of them were random hellish caves and complexes. Everything was even more furious and fast, too, which increased the frenetic rhythm to the action.

Why did this happen? We can look for a few causes that could help us to understand these differences. Everything was new in the first Doom, so it was easier to build the momentum.

In a sequel, however, you simply could not de-escalate the action. Hell had already appeared, therefore, there is no point in actually making the world change into it slowly. Repeating the strategy would be an ineffective idea. How to please the fans? By making the sequel even more brutal. Doom’s marketing was all about violence, after all.

The team followed the obvious path: to “upgrade” the game into something even more furious, but this also meant losing something along the way. Doom 2 lost some of its sense of marvel and progression while it added a rush fury of sprawling enemies and crazy mazes.

The second installment did use some interesting new elements like Earth’s cities, which are very different from any place that you could find in the first one, but they were only featured in a few levels. Soon you were in Hell again. In this context of chaos and pure fun, the addition of more enemies and a more powerful normal shotgun is obvious and it made sense.

The People Behind Doom

Both Doom games were created by id Software, which had already developed First Person Shooters before. Doom’s predecessor was Wolfenstein 3D, which was inspired by Catacombs 3-D, an older product of the company.

John Romero and John Carmack are certainly the two most recognizable names in the series, but there was one man that is possibly the reason why the two games are so different: Tom Hall.

Hall worked on Doom 1 and was fired because he was often arguing with Carmack. He was mainly focused on giving the project a more focused story. Carmack disagreed and wanted non-stop action sequences.

While the developer left before the product was finished, you can certainly see his mark. Most of the story he planned was scrapped and he declared his unhappiness after he left id Software by calling Doom a “raw shooter”, but not all of his work with level design and the foundation of the series was lost.

With the success of the brutality in the first Doom and with Tom Hall out of the way, however, the levels changed a lot in atmosphere and design. Romero designed many levels in both games and you can also see his distinct mark, but the second installment was mostly created by Sandy Petersen and American McGee along with Romero and the emphasis was a lot more on mazes and fast addictive brutality than story or ambiance.

These choices and the changes in the team created two very different experiences and show us a valuable lesson: every single part of a game is relevant. If you only take the most visible parts of it, everything will look the same, but sometimes the most important parts are the ones that are not so visible at first and they change the whole core experience.