With this Construct2D program you can be prepared in these games ?
Limbo,Harold,Ori and the blind forest,Best friends.
Or you can create with it are very simple ?
I think it is indeed possible to make similar games, but the more significant question would then become what about its efficiency?
I think Construct 2 is designed for lighter games in html5. Though it may be able to make amazing platform games like Ori, a lot of work is required due to its relative "stiffness" compared to Unity and this may cause lag issues
It can make games similar in functionality, and as efficient.
As long as they are 2d, and the creator is proficient.
They will not work very well on post modern machines however.
Construct2 optimized for very low compared to the Unity ?
Develop games in your browser. Powerful, performant & highly capable.
Optimised for what?
Yes it uses the smallest pixels possible.
I will never understand why people want to always compare a 2D engine with a 3D engine
If you use Unity you know that Unity devs take care not only about SDK but also about native exporters. If you use C2 you have nice editor but Scirra takes 0 responsibility about how your game will run on desktop and mobile. So if you have i.e. low performance on good computer then you can only submit/star bug on Chromium bug forum. And wait a few months for solution.
As far as I remember developer of Airscape had lots of performance problems and there is somewhere demo of his game. You can Google it.