The debate over whether Doom 3 is good or not will likely run until the day actual demons overrun the Earth, but it's fair to say id Software's threequel is a slower-paced experience than the other games in the series. It emphasises horror and atmosphere over raw, blistering speed, while combat encounters tend to have you battling handfuls of enemies rather than roomfuls.
If that's your bag, fair enough. But if like me, you found this resulted in a flat and uninspired shooter, then you might be interested in Runner's Doom 3, a mod which aims to make the game's combat faster, more intense, and more challenging.
Created by modder rulesnote, Runner's Doom 3 adjusts the game's core parameters to make it play more like a classic run-and-gun shooter. Some of these changes are easy enough to predict. The mod doubles the player's movements speed, removes the need to reload weapons, and increases weapon swap-speed. On the flipside, enemies are also faster and deal significantly more damage, while the mod also makes tweaks to specific enemy behaviours. Imps, for example, "will throw 2 or 3 projectiles per shot [and] dodge more frequently", while Lost Souls "will shoot you instead of biting".
Yet alongside these general alterations are some more ingenious changes. For example, the mod randomly resurrects "most" killed enemies a few seconds after they have been killed, presumably to make combat encounters longer and more intense. It also removes enemy spawn animations and effects, preventing players from killing foes before they can engage in combat. The changes to healing are a particularly good example of how the mod rebalances Doom 3. It lets you heal by "readying" your fists, meaning you can heal at any time in the game, but doing so leaves you temporarily unarmed, and therefore vulnerable to attack.
You can see Runner's Doom 3 in action in the video above. And I have to say, it looks a lot more entertaining than the Doom 3 I played back in 2004, faster without being too fast, and more action-packed without completely losing the game's distinctive vibe. I think I'd take this over remaking the game in Unreal Engine 5. I never had an issue with how the game looked, merely how it felt beneath the fingers.
If you fancy giving the mod a go yourself, you can download it over at ModDB. Note that there are two versions of the mod, one for vanilla Doom 3, and one for the BFG Edition.