I am not comparing Spark with Construct 2 negatively but I really think Spark is a dream Game Making Software. With it's event system for 2D and 3D will be it's strongest chess piece into winning the game developers. Not to mention it's native export that is not dependent to any 3rd party Wrappers. A nice forum just like Scirra and fun interface too. The downfall I only see is that the program is new and may contain many bugs, few items in it's asset store, may contain very limited features since it's new, a coding option that will be a sign that the event sheet cannot do everything the code editor can do, so everyone who uses Spark must learn how to code "Haxe" so you won't be left out of other advanced features.
Edit:
I read that the Spark Game Engine editor works on mobile, browsers and etc. and you can also make behaviors through the event system and very automated since you can right click on a sprite and add any behavior. That is very amazing if you think about it except, I think the browser part should be optional. Since the exporter they use is their own then this might just be the answer to all mobile export problems since they can just fix it when they find any bugs, that is if they aren't false advertising. If Construct 3 will have their own native exporter then it will be the end of headaches. <img src="{SMILIES_PATH}/icon_e_wink.gif" alt=";-)" title="Wink">
http://spark.tools/