When comparing Engine 001 Game Maker vs Unity 2D, the Slant community recommends Unity 2D for most people. In the question“What are the best 2D game engines?” Unity 2D is ranked 7th while Engine 001 Game Maker is ranked 62nd. The most important reason people chose Unity 2D is:
2D game creation was a major feature request from the Unity community and was added with version 4.3. 2D is provided in both the Pro and Free distribution of Unity.
Specs
Ranked in these QuestionsQuestion Ranking
Pros
Pro Light weight
An amazing minimal download size at around 100mb.
Pro Easy to use
Engine 001 allows you to get to making games quicker since you aren't putting allot of time into figuring out complicated interfaces.
Pro Visual scripting
By using pre-build behaviors\actions and more you can 'program' your game by simply 'linking' they in the editor.
Pro Built into Unity 4.3+
2D game creation was a major feature request from the Unity community and was added with version 4.3. 2D is provided in both the Pro and Free distribution of Unity.
Pro Integrates with Mecanim
Mecanim brings state machines and blending to 2D bone animation. The state machine editor allows for designers and programmers to visually create a Finite State Machine (FSM) to control when animations should play. Mecanim also allows for blending so an animation can transition smoothly between two states without the need of in between frames made by an animator.
Pro Sprite Sheet and Bone based animation supported
Both types of 2D animation for game development are supported in Unity’s system and can be used interchangeably in the timeline.
Pro Easily change sprites dynamically
Usually used for character customization, programmers can change any sprite in a bone animation at runtime easily by referencing the bone and loading the new sprite from the resources folder.
Cons
Con New tricks for getting more money
As it doesn't have enough tutorials, and they don't wanna make more, so they just add some new services about one on one help which that cost 40$ for an hour.
Con Windows only
The editor is Windows only, no OSX or Linux versions are planned.
Con 3D features may not be enough for some users
The 3D capabilities of the engine are a bit limited (for today standards), and some of the times you'll need to work around to create something.
Con Not for beginners
Even those few tutorials don't teach you the very basics, and first you must learn the basics somewhere else (the submitted pros are by professional guys).
Con No successful/ good games
Just ask them about games made with this engine and you will see that even if you find some good games, those are mostly simple/small ones.
Con Poor performance
If you want to use more than a few actors/light/events, or you're trying to get a pretty look, you will get a significant drop in frame rates. This is especially true if you want to implement a moving light (something like a flashlight).
Con They don't fix the bugs for you quickly
If you encounter a bug or problem and report that as bug report, it will take about 1 week to get any answer, and if they solve that, the fixed version will just come up with next update for engine which that isn't be soon and no specific time, so maybe you have to wait for one month.
Con Some workflows can be confusing
Sometimes you have to do a time-consuming workaround to just do a simple function.
Con HTML5 export is poor
There are significant drops in frame rate; some bugs that can even ruin your game (also, looks like just run on firefox).
Con No IAP or Ads support
Are you a mobile developer? If so it's good to know that it has export for ios/Android but no support for IAP or Ads.
Con Lacks critical features
- Vertices can't be animated, so you can't have ANY organic feel (like... lungs breathing).
- Parent bone can't be animated without affecting the children. This is especially impeding for organic feel, again.
- No option to show & unshow assets (or it is hidden), like for switching weapon on your character for exemple.

Con Poor script interface for texture atlases
Accessing individual sprites within an atlas texture is possible at runtime, but requires use of the Resources folder subsystem.
