When comparing GDevelop vs GameMaker: Studio, the Slant community recommends GDevelop for most people. In the question“What are the best 2D game engines?” GDevelop is ranked 2nd while GameMaker: Studio is ranked 6th. The most important reason people chose GDevelop is:
The whole interface is intuitive and easy to learn: each part of the game can be designed using visual editors. The objects editor is used to create the objects of the game, the scene editor help you to build the levels of your game and the events editor allows to give life to the whole game without programming.
Specs
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Pros
Pro Easy to use
The whole interface is intuitive and easy to learn: each part of the game can be designed using visual editors. The objects editor is used to create the objects of the game, the scene editor help you to build the levels of your game and the events editor allows to give life to the whole game without programming.

Pro Free and open-source
GDevelop's runtime libraries are MIT licensed. It can be used freely for projects of any type and there are no royalties associated with publishing games developed with GDevelop.
Pro Powerful events system to create games without programming
No need for coding using this system which is clear and powerful: events are composed of conditions and actions. Actions are launched when conditions are fulfilled.
This is a very friendly way of making games and is still efficient for advanced usage, contrary to most other "block"/"drag'n'drop" systems.
Pro Open source plugin SDK
The plugin SDK is open source, so if you want to extend it, you can.
Pro Lots of features to build games
The engine includes pathfinding, physics engine, multitouch support, custom hitboxes, platformer engine, tiled maps, multiple layers and cameras out of the box.
All of these features can be used without programming knowledge, using the visual editors.
Pro Quickly add behaviors to objects
Prebuilt behaviors can be added to objects. This is a very efficient way to add a physics engine or make a platformer game. Lots of behaviors are included, from the most advanced (Physics, platformer, top-down movement) to really simple one (like the behavior to destroy objects when outside the screen or the one to drag objects with mouse or touch).
And you still have full controls over your game as behaviors can be modified using the events!
Pro New documentation for gd5 is good for starting
A new doc is improving for gd5 that is nice for beginners and after that you can learn more from examples. Also, gd4 wiki is still there.
Pro Constant updates
New releases and bug fixes are consistent. New updates are released anywhere within 2 weeks or 1 month from the last one. Its auto-updater also does it job very well making life a lot easier.
Pro Online version available, compatible with iOS and Android
Thanks to its open source nature, GDevelop-App.com was built over the GDevelop engine.
GDevelop-App.com is a complete game creator similar to GDevelop, available directly in your browser and compatible with iPad and most Android tablets and phone! The app is perfect for making games directly from your sofa and you can even start a game on GDevelop-App and export it to open it inside GDevelop.
Pro Multilanguage support
GDevelop is available in many languages and even community can help in translations.
Pro Gives developers access to a more fine-grained controle over the logic through the Game Maker Language
Game Maker Language (GML) is the primary scripting language that is interpreted similarly to Java's Just-In-Time compilation used in GameMaker. It is used to further enhance and control the design of a game through more conventional programming, as opposed to the drag and drop system.
Pro Extremely easy to learn
GameMaker: Studio is incredibly easy to learn. It requires almost no programming knowledge which means that those without the technical experience, such as designers or artists, can create their projects without the help of a programmer.
Pro Easy to find resources/tutorials/assistance
GameMaker: Studio has a huge following, tons of people put up tutorial videos, and it's just generally easy to find help. It has a huge community.

Pro Easy cross-platform shader support
Write your own shaders in one shader language and have it automatically ported to all platforms. You can even choose a specific shader language to wield the full power of the target device.
Pro Assets can easily be found in the official marketplace
Yoyogames website has a marketplace which opens up an opportunity for people to sell or giveaway created assets and resources (sprites, scripts, sounds, extensions, full source codes, etc.) for use in GameMaker. This benefits people who needs quality assets for their games, and for creative people to provide these assets for extra income. The Marketplace has a rating system so it can eventually increase the quality and competitiveness of the assets submitted.
Pro It has an IDE used for loading all of the assets
It is very easy to manage all the resources you want to put in your game, the UI widgets for each assets (sprites, sounds, backgrounds, rooms, objects and shaders) are intuitive enough for when adding or even editing the properties of each your assets. The included editors are also good and easy to use (sprite/image editors, shader editor and room editor).
Pro Extremely stable
GameMaker: Studio has been around since 1999 and has been used and maintained during all this time. This makes it an extremely stable game engine.

Pro Cross-platform multiplayer support
There is the possibility of creating games that interact with different platforms and is not that hard.
Pro Built-in support for pixel-perfect collisions
Enabling pixel-perfect collisions on 2D sprites is so easy many will likely turn it on when maybe they might be better off without it. Regardless, it simplifies small and/or retro console-like game work. This is a feature fairly unique in this class of game engines.
Pro Cross-platform
GameMaker: Studio projects can be deployed to: HTML5, Linux, Windows, OS X, Windows Phone, Android, iOS and PS3/4/Vita.
Pro Easy to use
Game Maker Studios simple interface allows for rapid prototyping, and easy development.

Pro Supports 3D
There is also 3D support that doesn't interfere with the primary 2D focus.
Pro Easy to add native code to GMS
Good extension support. You can do anything with gms! You just need to know how to code natively in the respectively export (like Android).
Cons
Con No support for atlas/tilemap and sprite sheet
At this point, you need to separate the tileset maps or character animation sprite sheet before importing it to the engine, but the developers are working on this feature.
Con GUI is slow to load
This makes doing the simplest things, like looking at one of your maps, hard to do. In looking into this program, it can stall a PC while trying to load a sample map.
Con No 3d, not even fake 3d
This is a 100$ 2d-only game engine. You could of course use pre-rendered 3d graphics, but your games themselves will exist only in the x and y axes.
Con It's very slow
Although suggested otherwise, GDevelop doesn't compile the games - it just adds wrappers so each OS can run the HTML5 game it creates. That means it runs much, much slower than other engines that do compile games.
Con No cross-compiler
The Windows and Linux versions of GDevelop can each compile a native application; but the Windows version cannot compile for Linux, nor vice versa.
Con Optional subscription not mentioned on main site
While the engine is free and open source as stated on the main website, it does not mention that some optional features and services are actually activated through a paid subscription (two tiers: 2€ and 7€). Those features are: no nag screen shown when debugging, additional metrics available on games dashboard, access to more than 2 cloud exports per day (unlimited local export can be done without subscription, provided the right packaging tools are installed and configured), easy removal of GDevelop splash screen (can be done manually without subscription).
Con Behaviors of Objects are rather generalized
Since it has a fully GUI editor, the objects you are allowed to add in your game are pretty generalized (PhysicsObject, TiledSprite, PlatformerObject, etc). This limits the freedom of a game developer while making a game, as the object msut follow the preset behaviours imposed on it.
Con The scripting language used is quite limited
Language does not support actual objects, structs, real data types, functions, overloading, even argument naming. Developers generally have to code around the lack of these features in very tricky ways.
Con No GUI editor
The GUI must be hard-coded, leaving a lot of tricky calculations and jumping through hoops to accommodate different devices and displays; it's probably the least developed and hardest thing about GMS2 compared to comparable engines

Con Destructive DRM
In late 2012/early 2013, YoYo Games released a version of their new Studio IDE for cross-platform development that would import games and destroy all of the image type resources for some legitimate purchasers of the software by superimposing a pirate symbol on top of the image. This was due to a fault in their digital rights management software implementation which they use as a method of combating pirated copies of the software. Though the false positives bug is reported to be fixed, the DRM is still in place and may affect placeholder graphics, etc. YoYoGames publicly stated they would remove the DRM at a later point in time, but that other less-invasive DRM techniques would remain.
Con Exporting to some formats costs extra
You need to buy extra modules to be able to export to platforms like Android, iOS, HTML5 and others.
Con No built-in refactoring tools
There are no built-in refactoring tools. For example, you can rename a resource, but GM:S will not automatically change the mentions of it across the code to the new name. Furthermore, because all file formats are text-based, basic refactoring could be achieved by simply doing "find & replace in all files" -- which is a feature offered by pretty much every external code editor nowadays -- but no such feature here. Hitting Ctrl-F will pull up a rather odd Find/Replace box but selecting a word before hitting Ctrl-F will not autofill the Find field for you like it will in most tools. Even that you have to cut and paste yourself.
Con The cost to buy for development is outrageous
The cost for this tool is hindering for indie developers who have little money to work with.
Con Bad history of ignoring critical bugs
In the past, the developer failed to update the software for iOS and Android when game-breaking updates were made to those platforms.
Con Development has been and will be cosmetic
The change from 1.x to 2.x was cosmetic, the engine and language stayed the same. The roadmap for future development is also cosmetic and includes updating the sprite editor, adding an audio editor, and adding a "mini map" for the IDE.

Con Poor level editor
No marquee select, no layers, can be glitchy, no grouping, etc.
Con Can't embed videos in game
Doesn't support embedding videos in a game.
Con Expensive for what it offers
There are several options with more flexibility, better learning resources, and a lower price point.
Con Proprietary language forces expensive "lock in"
Because it uses GML, a very non-standard custom language, new users do not learn a transferrable language and become locked in.
Con Tends to crash or not compile games properly
Con Poor accessibility and integration
Documentation and resources largely focus on proprietary scripting language, which is necessary for achieving full potential of the software due to poor drag and drop integration.
Con No way to activate or use existing modules
Support entirely focused on new iteration depriving even basic functionality of this version with any purchase that hasn't already been activated. It is still possible, thought not intuitive, to download this version on the trail screen for GM S 2. But no purchased (wildly expensive) module can be added any longer.
Con Code editor not friendly to indented code
While the editor of course has features for intending code such as auto indent and smart tabs that can be turned on or off, these features work in unusual ways and, overall, the editor is not very adaptable to various typing styles. Also, Home always takes you to position 0 and never to the beginning of the text no matter how many times you hit it. Thus, if you hit Home and then Enter a new line, with auto indent on, it will always mess up the indentation on the line following the new line leaving you to fudge around to fix it manually. If you prefer tabs over spaces, forget it. Finally, if you leave the GameMaker app and try to click back into the code editor, the code editor will not fully get the focus sometimes leaving you with the ability to type but not tab. It usually takes two clicks to fully focus the code editor from outside the GM app.
Con This is very flat for games
They are not beautiful - for example, Undertale.
Con Owned by a gambling company, Playtech
As opposed to other engines, which are open source or owned by game companies, GameMaker is developed by YoYoGames, which is owned by Playtech, a gambling software company.
