Hi sqiddster! Thanks for your reply!
Yes, the game is actually for mobile, and must be HTML5 based. So I thought it was a good idea to make it with Construct.
I was worried about efficience too. I am new making HTML5 games (but no in game development with lots of another languages) and I was wondering how difficult this can be with C2 and HTML5 in general too!
I still didn't accept the project, so if there still time to avoid it.. good to know it! XD
But if there is a good chance to makes it work with C2 for mobile, then I will aim for it!