When comparing Solar 2D (formerly Corona SDK) vs ct.js, the Slant community recommends Solar 2D (formerly Corona SDK) for most people. In the question“What are the best 2D game engines?” Solar 2D (formerly Corona SDK) is ranked 15th while ct.js is ranked 56th.
Ranked in these QuestionsQuestion Ranking
Pro Very simple to use
Corona SDK is completely free. That includes pro-tier plugins.
Pro Corona Simulator
Corona SDK ships with Corona Simulator, which runs your game/app directly on your PC/Mac and updates every time you make changes.
It provides immediate feedback to your actions, you can see your changes right on the screen, without necessity to make build to device. Getting instant feedback really boosts tenfold prototyping and development speed.
Pro Lua syntax
Uses the great and easy-to-learn Lua programming language.
Pro Very comprehensive API
It's very quick to get things up and running with Corona SDK. The API is extensive and while it's not 100% feature-complete with the iOS API, it's close enough that you could create tons of games and never run into a roadblock.
The API docs can be found here.
Pro Amazing learning curve
Corona does not throw photoshop-like madness full of buttons editor. You can go as fast as you want, learning and building game from ground up. Eventually, you'll learn how much corona is doing for you. But to start you don't have to master complex editor software. It's a great tool to learn to start game development if you want to learn how to program and make games. Your experience will be 100% transferable to any other Pro game engine.
Pro Good documentation and lots of tutorials
Pro Cross-platform desktop and mobile
Corona works on OS X, Windows and Android (including Kindle Fire & Nook).
Pro Content scaling
It's easy to create a game that looks good on many different sized mobile devices.
Pro Live builds - update builds running on a device automatically
With the live build feature, once you have created a build and installed on a device, you get lightning fast turnaround times because any change on the code or data is updated to the devices running the game (within the local WiFi) immediately. So changes can be tested on the real hardware within a very few seconds.
What's even more impressive, this even works flawless with multiple devices running the game. You have to use it to learn how good of a feature this is while development and even more, while doing QA. Imagine fixing bugs and everyone of your QA team/friends/whoever helps to get your game done, has all changes on his device without doing anything but waiting 5 seconds - outstanding.
Pro Marketplace for 3rd party plug-ins
Pro Great community
Pro Ability to call any native (C/C++/Obj-C/Java) library
Pro Open Source
Since Corona SDK became Solar2D, it's completely open source under MIT license.
Pro Completely free
Since Corona SDK became Solar2D, it's completely free, as only some third-party plugins are paid.
Pro Well supported
ct.js is bundled with examples, docs, and easy to follow tutorials. Documentation and tutorials are available in a side panel on every screen.
Pro Skeletal animations with DragonBones support
You can import skeletal sprites and animations from DragonBones, which is also free. Skeletal animations are added to objects through code; developers can listen to marked events in animation, and ct.js automatically associates sounds in a DragonBones project with the game's assets.
Pro Good code editor
The built-in code editor comes with error checking, type checks, code completions accompanied with docs, multiple cursors support, and other modern features.
Pro Open source (MIT)
This means that no one will ever put any features behind a paywall and that you can reliably use ct.js in any projects without worrying about licensing. And you can hack on ct.js!
The repo is at https://github.com/ct-js/ct-js
Pro Tileset support
ct.js supports tiles in rooms, including collision checks and some extra editor tools, like bulk migration to a new tile layer or shifting by an exact value.
Pro WebGL and WebGL2 support
Starting with v1.0.0-next-1, you can now write WebGL games. WebGL support is based on Pixi.js.
Pro Modular approach
ct.js has a "Core" library that provides basic drawing functions, room and asset management, and mouse interactions. Any other functions are added to projects as "catmods", or simply modules. These modules can be enabled or disabled in one click, and can inject their code in different game loop stages, e.g. after drawing all the objects, leaving a room, or when a new object is created.
Pro Applicable to most genres
ct.js aims to be a general game engine and provides tools in making games of any genre.
Pro Dialogue and visual novel system with support for Yarn
A module ct.yarn allows developers to import a YarnSpinner project to create branching, data-driven dialogues and visual novels. An example is also bundled with ct.js.
The dialogue tree is made in a separate app, though.
Pro Real-time particle system editor
v1.3 brings a particle system editor, which displays a preview sprite for proper attachment of emitter to visual elements, and allows combining more than one emitter with different particles into one effect. With these, even the creation of complex, multi-step effects becomes easy. The editor comes with dozens ready-made textures for faster prototyping.
Con Closed source
Con Free, but not completely
Con Making a device build requires internet connection
To build your app for the device (iOS/Android/AppleTV) Corona requires to fetch resources from online. This would include base application template and plugins. This allows not to perform local build or use Xcode or Android Studio to do a build. Even Large games/apps would build very fast with good internet connection.
Your code never leaves computed. Corona SDK would transfer some information to determine which plugins and pieces has to be transferred in order to make a final steps in build.
As a bonus - you get basically one button press to get from your Corona Simulator game to game on a device.
Con Tile editing is a chore
No live brushes with automatic corner drawing, no fills or rectangular/linear placement. All tiles should be placed by hand, with a "Shift" key to place multiple tiles at once. This will make you ragequit if you want to make sophisticated RPG scenes :D
Con Slower than native games