Construct is a very simple and easy to use engine by Scirra, a London-based company founded by Ashley and Thomas Gullen.
The engine is presented as an application that allows you to create your own 2d games without the need for coding.
Indeed, you can create your games without the need to write a single line of code.
Construct uses a combination of behaviors and events to add functionality to the different objects in the game. For example, adding a specific movement behavior to an object will allow you to setup that object as an 8-way movement character for a shoot them up kind of game.
There are a variety of behaviors that you can use to add different functionality to an object, like turning an object into a bullet, turning an object into a platform or adding physics to it.
Events are the other part of Construct that allows you to add functionality to your game.
Events are pretty much "what happens (output) if a certain condition is met, or if certain something happens (input)."
For example, what happens if a bullet hits a specific object, or what happens if you press certain key or button. What's nice about events is that you are not limited to a single "output," but rather you can tell Construct to unleash a lot of different outputs based on that single input.
As I said before, Construct is a 2D engine, and objects are created from images.
You can technically use any kind of image format, but certain formats are better than others, due to image compression or transparency support. You can even create animations if you import a series of images when creating an object.
Also, objects in your scene (called "Layout") can be organized in layers, so it's easy to select objects while ignoring other kinds of objects. As your layout gets more populated, it can be difficult to select exactly the object you want, so being able to order objects into layers means you can lock or hide certain layers, making it easier to work and select objects in your scene.
Construct is also a multi-platform engine, which means you can make games for PC, Mac, phones, web, and other platforms.
According to the website, you can even make games for the WiiU (though the WiiU is pretty much dead now that Nintendo is focusing on the Nintendo Swich).
The free version of Construct allows you to make games for web, Windows Store, Chrome, Facebook and Scirra arcade. The paid version also lets you make games for Windows, Mac, Linux and Amazon Store.
This means that, even if you are using the free version of Construct just to learn game development, you can distribute your games for others to play via web or Facebook.
Using a "code-less" engine like Construct will obviously impose some limitations to the kind of games you can make.
However, I think this can be an advantage because you don't get stuck in the "technical" side of doing something, allowing you to focus on the design side of things.
Having said this, Construct can be a very adequate tool for those who want to get into game design, as it allows them to try out their ideas quickly, without the need to struggle with the technical stuff.
At the end of the day, remember that a simple game with good design is better than a complex game with bad design.
Those users can then move on to a more complex engine, like GameMaker or Unity, in case they want to make more complex games. If you want to try out game design, or game development for the first time, Construct can be the tool for you.