Here is my go.
I have used big font, you should have big font, big font is eyecatching!!! And my font is so big it doesn't fit on the picture! You can't get better.
Also I used comic sans because it's happy apps, and comic is funny, funny, happy, see the connection?
I liked the other one with the smily face that is good vibe for a logo, so I put one in. I used bright colour for eye catch and make feel happy!
But the face is done in soft brush, looks like blur doesn't it, that's depth of field, fancy effect right there.
Pick mine, srs.