When comparing Kerbal Space Program vs Garry's Mod, the Slant community recommends Kerbal Space Program for most people. In the question“What are the best indie games on Steam?” Kerbal Space Program is ranked 8th while Garry's Mod is ranked 47th. The most important reason people chose Kerbal Space Program is:
The physics engine does a reasonably accurate job of replicating the fundamentals behind both orbital dynamics and rocket design, so by going through the tutorials and experimenting, you're actually learning some real rocket science.
Specs
Ranked in these QuestionsQuestion Ranking
Pros
Pro Teaches orbital dynamics & rocket design fundamentals in an accessible manner
The physics engine does a reasonably accurate job of replicating the fundamentals behind both orbital dynamics and rocket design, so by going through the tutorials and experimenting, you're actually learning some real rocket science.
Pro Tons of stuff to do
Build rockets, space planes, space stations, rovers, landers, probes. Explore planets, moons, capture asteroids, set up a communications network, colonize a planet, mine for resources and much more. It can even simulate our solar system.
Pro Huge modding scene
There's a plethora of mods available that can change every single aspect of the game.
Pro Excellent construction sandbox for building and launching rockets
KSP at its core is a rocket building and launching sandbox. When creating a rocket you can place engines, fuel cells, structural elements, and even parachutes, allowing you to build a rocket in any shape and size. The end result can even look like a giant doughnut, which might be difficult to get it into outer space. Even if you fail, the entirety of the process is really enjoyable.
Pro Motivates you to learn
Kerbal Space Program puts into perspective how amazing the advancement of the human race is. It inspires you to learn our history, how we got here, and what we can do proceed.
Pro In constant development
KSP is a shinning example of early release done right. The currently available game is fun to play, and the developers are constantly adding new major additions.
Pro The games mechanics and mods allow for ridiculously funny gameplay
You can do some really crazy things in this game thanks to all of the community mods available as well as the built in, in game tools. Pretty much any scenario can play out in the game, if you so desire. Of course the winning combination of funny tends to be when players are just goofing around.
Pro Tons of community made add-ons allows the game to continually grow
Garry's Mod has a wide variety of community made add-ons, which deeply extends the games content and versatility. Pretty much, if you can think of it, someone has probably already made it.
Cons
Con Some visuals are poorly done
While the rockets, buildings, and even the Kerbals look pretty good, the environments and particle effects are a bit lacking.
Con Steep learning curve
Kerbal Space Program is not really a pick up and play title. It can take hours just go grasp the basics and the game will keep throwing new concepts at you as you progress into space, even stuff like orbital dynamics. Because of this, it can easily take dozens of hours to truly master this game.
Con It has nothing to tell as a campaign. Tastes like void, that is "meh".
Con Previously free to download
Garry's Mod used to be a free download but it is now a paid game on the Steam store.
Con Tons of bugs
At least in earlier versions.