The simplicity along with the muted colors really make this shot. I like how he's wearing slippers and she appears to have dress shoes on, this tells a nice story. It's not a date (and least I would never wear slippers out) so they've known each other for a while, yet they still play. I could be wrong and those are shoes, but it works either way.
Sometimes, taking pictures of feet/shoes is overused. BUT I'm a fan of how you captured this, framing is pleasant, and I'm a big fan of the vivid color.