From Emanuele Feronato: "One of the most interesting features introduce in platform games is the ability to jump on enemies and maybe squashing them to death.
I am not sure which game was the first to introduce this feature, I would say some chapter in the Mario Bros series, although I am pretty sure in the very first game you couldn’t squash enemies.
Anyway, we are going to see how we can develop this feature in our HTML5 games using Phaser and ARCADE physics."