I have seen some pretty large games made through Construct 2 already that play fine on my Android device. From what I gather so far, Construct 2 performs fine granted you keep in mind the limitations of the platforms you are programming for and make sure to use your resources wisely. There are probably 10 different ways to implement a specific feature into your game but you are going to want to use the least complicated way that has the smallest footprint.
As others have said, because of the broader target audience of Construct 2, it allows for poor code practices. The better you are at organizing your project, events, objects, so forth, the better your game will probably run. There are also a multitude of resources on this site that address things like do and don't, gotcha's, and general tips when it comes to performance:
https://www.scirra.com/tutorials/top/pa ... e=detailed