Some good, some bad.
A very mixed bag.
It's a shame that all of the things apart from #12 were just mcs being spawned at the point of your mouse.
I really liked the change in #12 and had fun imagining other possible ways to interact - hoping you'd do some of those things and more.
The different shapes and animations do encourage different sort of movements as we're interacting in order to make pleasing shapes though - something I like.
And yet, there's an awful lot of repetition and a fair few that I think could have been cut out in the name of improving the overall impression. There's a good few variations on each possible movement pattern when it may have worked better to just focus on the best few.
The representational smiley faces felt trite compared to the abstract stuff and the thin black lines around some shapes looked unpleasing to my eyes as did some of the 'hand-drawn' stuff. The geometric shapes look kind of classier and seem better suited to being repeated as particles.
There's a fair few Flash on NG that spawn particles at mousepoint already but if you pursue different ideas in how the particles could move and be interacted with - something I hoped you'd do after #12 - I'd love to see a sequel.
Bird in Flight was cool too.