The Strengths of GURPS

GURPS is like 5E in that the characters are the strongest part of the game. You could argue that 5E is "GURPS in slow motion" since you are building a character of equal complexity, slowly, over 20 levels. Your choices in 5E are severely limited by the designers, first in class, and second in subclass, and you can only break that cycle through multiclassing. Still, even with multiclassing, you only get 5-10% the design flexibility of GURPS.

And also, in 5E, you pay a lot of money for each option. Playing 5E is expensive, and your design options are sold to you a few per book. If a sixty-dollar book has six new subclass options, and the rest is setting  info and adventures, that is ten dollars per option.

In GURPS, everything comes with the core books. All options. All powers.

In theory. Specialized books for designing powers and magic spells exist, but those give you more. You can theoretically design any power or spell you would need with the core books only, so the expansion books just exist to save you time and provide ideas.

If you are missing a 5E book with options you want, you are out of luck.

In GURPS, it is not really a problem. It may be a little more work and research, but you are not being limited by not having one of the expansions.

You are not slowly paying extra for years. This is the D&D and Pathfinder design model, and it has been costing gamers a ton of money since Wizards took over D&D for nearly 25 years. Yes, you can play with the core books only, but if you want options those books don't give you, you are going to pay a lot of money.

Again, you will eventually get a game with as many options as GURPS, but it will take you 15 years and a few thousand dollars. I have that with Pathfinder 1e, finally.

There is probably a story of someone who has only bought the core two GURPS books in 2020, versus someone who went through D&D 3, 3.5E, D&D 4E, Pathfinder 1e, D&D 5E, Pathfinder 2, and now D&D 5.5E. That person would likely be me (except for 5.5E, which I will never buy into), and I feel stupid for getting strung along so long. Yes, I enjoyed the books and had fun, and that is what matters, but five versions in 25 years means a new library of books every five years. I feel I need to constantly replace my D&D books, and any version of the game breaks quickly.

Versus one library, 2-3 shelves, of GURPS books that keep their value much better.

Another strength of GURPS is its combat. This combat system has held its own since GURPS 1.0, and it really has not changed all that much. Skill has meaning, and fighting a skilled opponent is hard. Your choices matter, and you can use skill to make huge bets - for huge payoffs. You can also take that "arrow to the knee" and start a chain of events where you will never be able to jump that chasm you easily jumped on the way in, and you slowly realize the fact you are not getting out of this dungeon alive.

From a single knee wound. In 5E? Short rest, and it magically heals. And there are no rules for a limb being wounded, so it does not matter anyway, and if a referee pulled this in 5E, the players would accuse the referee of being "unfair" and "breaking the rules." D&D is a videogame. The pen-and-paper mobile game MMO they wanted 4E to be. Death means nothing. Just respawn back at your bastion.

In the OSR, you make a ruling. It takes an imaginative referee to decide a wound that took away 25% of your hit points is that "knee wound" and what that does in regard to jumping that chasm. Maybe you rolled a hit location, in most cases you didn't. There is a lot of "just say" in the OSR, and that requires a bit of skill and experience in refereeing. It also requires a level of maturity from players to accept that ruling and ""go with it." Otherwise, the OSR is like 5E, and many referees just treat characters as a bag of hit points.

In GURPS, it is what it is. It happened. Maybe the hit location was random, and that is where the arrow landed. Maybe your character's legs were lightly armored. These were all choices you made, or things that happened due to the game. There is no "just say" here in regards to combat, but there could be if you play theater-of-the-mind. Still, there is always a way to determine hit location and what happens next.

The immersion in GURPS happens through discovery and realization you may have pushed your luck just a little too far, and now you are fighting a battle of how to get out of there alive. You can still make those OSR "rulings" in GURPS, but a lot of the game makes those for you where you need them. The guesswork and "making stuff up just because" is gone, and the game is easier to run.

Everything in GURPS is "zoomed in" a level, and it is sort of like Rolemaster's level of detail, but more physics-based and logical. When you defeat one foe, you feel a sense of accomplishment. The combat was likely gritty and real-feeling. The threat to your character was real, one lucky hit is all it takes. This is also why most OSR and 5E modules don't convert well into GURPS, there are way too many enemies in those adventures.

Take a module like Keep on the Borderlands, and it is happy to have 20-40 monsters in a room, and many rooms have 6-10 monsters. Some of these combats would take forever in GURPS played in-detail, unless a lot of GM fiat and simplification were used.

Even a game like Savage Worlds will simplify foes into "groups of enemies" and handle them as one. You see a few methods of handling large combats in several games, from D&D 4E's minions, to grouping foes, to keeping hit points low. My B/X mod uses original "hit points as rolled" from B/X, which could lead to goblins having 3 hit points in GURPS. And that is fine! One hit will take the goblin down, which makes the monster like a minion in D&D 4E, and in a dramatic and cinematic sense, that works in the style of game I am running.

For most of these group monsters, I will use GURPS Ultra Lite. Give the monster hit points, an attack skill, an acceptable parry/dodge number, a speed, and an armor value - and you do not need a bestiary or monster manual for any of them. If you want tough orcs, give them a higher STR and more hit points. Roll hit points for every monster, since they may enter the adventure in various states of wounds, health, and recovery, it is not an easy life being a monster.

Most monsters can be converted from B/X sources, once you know GURPS after a few combats. this isn't 5E, where first-level balance is a lot different than tenth-level balance. Numeric balance in GURPS stays relatively similar, which makes conversions a lot easier, and this is also why I really dislike the scaled damages and hit points of D&D 3.0 and beyond. The original White Box, First Edition, B/X, and BECMI hit points and ACs were just fine - and convert easier into GURPS as a result.

Not treating monsters as characters speeds up play, and also keeps the characters as the center focus of the game. The more you focus and play to the strengths of GURPS, the better your game will be. If monsters bog down your game and you find yourself slogging through them and your game feels slow - simplify them!

Focus on the game's strengths: the characters and the combat (if combat is a huge part of your game), and everything else can be simplified to just a few important numbers. You don't need to "port in" everything either, if you are doing a GURPS Car Wars or Star Frontiers, and find the original game's vehicle and ship combat rules work fine, use them! You can always make all skill rolls in GURPS and guesstimate modifiers.

Characters and having the control and design of exactly what you want is the core part of GURPS. This is the part of the game that returns the greatest satisfaction and enjoyment. Seeing how the design interacts with combat and the world is why you put the time into these designs.

Everything else is secondary. If you find something dragging down your game and leading you into endless conversion projects - stop, simplify, toss out, and borrow systems that work better.