When comparing Phaser.io vs Unreal Engine 4, the Slant community recommends Phaser.io for most people. In the question“What are the best 2D game engines?” Phaser.io is ranked 8th while Unreal Engine 4 is ranked 17th.
Specs
Ranked in these QuestionsQuestion Ranking
Pros
Pro Great community resources
Pro Built-in Arcade Particle system
Pro Very active development
This is one of the most developed frameworks right now.
Pro WebGL and Canvas rendering modes
You can choose WebGL or classic HTML canvas element for game rendering.

Pro Good tutorials, courses and books
There are plenty of great learning resources available for Phaser.io.
Pro Super-simple loading of assets
Pro Excellent tools for sprites
Pro Support for Arcade Physics, Ninja Physics and p2.js
Pro Easy to learn
Most tasks are done just using 2 or 3 lines of code.


Pro Very fast to develop with
If you're browsing Slant, you probably already have a JavaScript enabled browser, which is most of what you need to get started learning JavaScript. The requirement to run a server locally on your computer while developing might make things a little more difficult
Pro No install required
All you need to do is attach Phaser script to a HTML page even without installing any extensions.
Pro Easy to understand if you have used flash
Phaser provides a similar approach as to that of Flash games, where you can load assets and place them on a stage, and even improves upon the shortcomings of actionscript. It is very easy to shift from flash to HTML5 development because of this approach.
Pro You can run it in the cloud
You can use it in popular online editors like replit, codandbox, etc.
Pro Animating is easy
Pro Has separate versions maintained by developer and the community
The creator of phaser(photonstorm) has given the older(Phaser 2.0) source code to the community for their own maintenance, and has made Phaser 3.0 with a different style and approach, trying to make it easier for beginners to learn.
Pro A visual scripting system for non-coders enables quick prototyping
Blueprints are authoring tools designed for non programmers so designers and other team members can help tweak and prototype. UE4's Blueprint scripts resemble flowcharts where each box represents a function or value, with connections between them representing program flow. This provides a better at-a-glance indication of game logic than a simple list of events, and makes complex behaviors easier to accomplish and games a lot faster to prototype.
Pro Lots of resources to learn from
Epic provides multiple official video tutorials, lots of free example projects and content, an extensive wiki and regular streams showing how to use latest features.
Pro Powerful material/shader system
Allows a texture/material artist or VFX artist to create amazing effects from the ground up.

Pro Free development license, including source code
The engine, including full access to source code, is free to use; a 5% royalty is due only when you monetize your game or other interactive off-the-shelf product and your gross revenues from that product exceed $1,000,000 USD.
Pro Realistic graphics
Pro Developers have full control of the engine and source code
UE4 gives full access to the C++ source code allowing editing and upgrading anything in the system.
Pro Dynamic global illumination with voxel cone tracing decreases the computational power needed
Voxel cone tracing is a similar algorithm to ray tracing, but uses thick rays instead of pixel thin rays to be able vastly decrease the amount of computational power needed.
Pro Easy to use animation blueprints
Unreal Engine 4 is one of the best game engines. It is super easy. It dosent require any use of coding due to Animation Blueprints
Pro Spectacular lighting visuals
Pro Cross-platform editor and export
This engine exports for a big range of platforms including Linux. The editor can be run on Windows, MacOS, and Linux (Early Access).
Pro Active community
Forums have many active and friendly members that are quick to respond and help out. Even staff is very active on forums.
Pro AAA Ready
This is ready to make the next AAA game.
Pro Fast compilation for quick iteration
Recompiling an entire game to test a small change takes up a lot of time. UE4 quickly compiles in seconds instead of minutes improving iteration time by an order of magnitude.
Pro Quick release-cycle
New feature releases can be commonly expected about once a month.
Pro Professional feature set for all aspects of game development
Almost everything a game developer wants has a deep and sophisticated tool waiting for them in UE4. No external plugins are needed to make powerful materials, FX, terrain, cinematics, gameplay logic, AI, animation graphs, post process effects, lighting etc.
Pro Proven track record
Pro No coding experience needed
Cons
Con Using Cordova to Export for Mobile
To export to mobile games you need to use cordova.
Con Official documentation is not so good

Con Poor performance
As long as your map is not larger than 600*400px, everything is fine.
Con Extremely many bugs
Con Developer ignores community needs
Con Very high build size
A blank project will build in to a minimum of 200 MB.
Con Slow
Compared to other engines, UE4 seems to perform various actions considerably slower. Actions like starting the engine, opening the editor, opening a project, rebuilding shaders, updating references, calculating lightmaps, saving projects, etc take long enough to get irritating and end up wasting precious development time.
Con Extremely long build times
Making a full rebuild, including engine can take a good 30minutes. If you plan to use Unreal professionally, you better get some licenses for Incredibuild as well.
Con Hard engine for beginners
This engine not easy for beginners
Con Steep learning curve
Especially when compared to its primary competitor, Unity.
Con No drawcall batching, performance is very bad on mobile
There's no dynamic batching support to minimize drawcalls. There's InstancedStaticmesh concept in UE4, but it's 3d only, functionally limited and requires hardware support which rules out most mobile devices.
Con C++ - oriented development cycle: slow turn-around times
The Unreal Editor is the main place to do stuff (of course), so if someone wants to do a lot of C++ stuff, the compilation and linking turn-around times can be painful. Still they probably are quite fast in comparison to the provided featureset.. Still ,they are far from optimal.
Con Poor documentation
Most of the "documentation" for code is actually just automatically generated from the source. If you're interested in knowing how things are supposed to work, you must either go to their answers site or pay for UDN.
Often their examples won't even compile, since they were written for now outdated versions.
Con Royalty based
5% of profits will go to Unreal after $3000 earned in a quarter.
Con They spend more time adding features than fixing existing ones
Con C# not natively supported
UE4 does not support C# natively, but this can be achieved through MonoUE, although it requires using the MonoUE fork instead of UE itself.
Con Poor source control support
Merge tool is not working.
Con Poor quality assurance on their releases
After each release they almost immediately release a hotfix. And another one. And another one.
Con Unreal Engine crashes a lot if you don't have the required system requirements
Con Sparse Resources for C++
C++ happens to be the main suite for Unreal, yet the documentation is very, very sparse.
Con Extremely poorly designed
The code is a mess.
Everything is connected, a single Actor is 1500 bytes, because it contains a million things that Epic once needed in a game.
Inheritance for AActor: AActor > UObject > UObjectBaseUtility > UObjectBase
Con Difficult for Mac users
If you're installing it on Mac, you simply download Epic games launcher and watch it download nothing endlessly.
Con Tutorials do not go in-depth enough
The blueprint tutorial just teaches how to turn on a light when you press f.
Con Proprietary
Con Not available on Linux
Con No Terrain Editor included
Con Bad support
The epic games team only assists with billing and account issues, not bugs.
Con Terrible physics

Con Frequent crashes
Often the editor crashes interrupting your work.
Con Poor error messages
Con Rarely works
