DOOM differs from most modern shooters because it abandons cover-based gunplay and instead encourages you to never stop advancing. This is achieved by not only making your character very nimble, allowing you to run at high speeds and jump great distances, but also by removing weapon reloading entirely.

There is also the glory kill system, which restores your health whenever you melee kill an enemy, so no waiting for your health to restore by itself either.

All of this creates exhilarating gunplay where you never have to pause for anything.

The levels in DOOM are quite large, with multiple floors/levels, and many secrets. Some areas are very spacious, making large-scale battles possible, and some are labyrinth-like, hiding enemies behind every corner. You'd think it would be a very linear and guided experience, but most of the time it's up to you where to go and how to get there. Each one of these aspects make it a blast to fully explore the levels.

The game comes with a level editor, which allows you to create new maps and game types. These can be maps that play similarly to the campaign or even unique puzzle maps. You can share your creation online and also download other players' creations. This provides an almost endless stream of content, adding considerable longevity to the game.

Highly detailed environments, fearsome enemies, colorful particle effects, beautiful lighting, and a lot more. Whatever you're looking at in DOOM, it's a treat for the eyes, all without ever dropping below 60 frames per second.

There are more than 20 weapons in DOOM, including the super shotgun, the rocket launcher, and even the BFG9000. Each weapon has two modes that can be improved with one of three upgrades, totaling to over 100 possible combinations. Most of the combinations are really fun to use, which creates enough variation to keep you entertained for multiple playthroughs.

There is no character development, this is a single purpose game that makes itself very clear from the outset. You are in this game to do one thing, kill demons, sometimes in the most gruesome ways possible. The game is very unapologetic about this, which is refreshing in a time when many games focus on story and play out like an interactive movie. This is much more a throwback to simpler times, run and gun, and it can be quite fun.

There are quite a few easter eggs and hidden secrets in the game, such as old school Doom 95 levels, a Commander Keen skull, a Terminator 2 animation, and even hidden Doomguy toys that your character will fist bump. There's a lot of these to find, creating a very entertaining side activity.