Things that can be improved:
Power. C2 gives you the most basic things you need, but lacks when you want to do some really polished stuff.
If you respect the recommended best practices and follow the performance tips (as well as use image compression efficiently) you can already do pretty polished games.
And webGL shaders are already on their way too.
I could find mid point between closest image points of both objects, but then they are instances of the same object type! and the only way I could get around filtering based on instances is comparing between families. Now when I try to do that, I lose the additional data I require from my original data type, for e.g playing a fx based on velocity (which I cannot retrieve from just families).
Two things here.
First have a look at this post giving the first clue about "index picking" and have a look at the topic listed in the section "Picking/selecting instance(s)" in the how do I FAQ you can see picking is way powerful but tricky to master.
Also for now, families make you "lose the reference" to objects, but be aware that families variables and families behaviors are on their way already. Families were recently added and are still more or less a WIP, an active WIP.
I guess if we can expose some of the core stuff within the engine, we would able to overcome these, but of course I do not know how far this is possible, but anyway.
Have you had a look at the SDK ?
This contains all the things and exposed methods to make custom plugins and behaviors in javascript. The manual is comprehensive and quite exhaustive and the javascript SDK development's forum is there to cover all the missing spots or devs questions.
On a final note, I really enjoyed the short period I have worked on C2, and really hope this keeps expanding, and we can make some awesome games. :D
Imo we can already do awesome game, and seeing that still less than a year old, C2 is soon to hit its 78th release, I'd say it keeps expanding and will keep on for the foreseeable future without a doubt.
Welcome on the forum and enjoy using C2 <img src="smileys/smiley1.gif" border="0" align="middle">