The differential is the fact that you're somehow carrying over the hearts through Oro kills. But leaving that aside, what exactly would you DO with the hearts?
It has half-life 2, half-life 2 episode one, and half-life 2 episode two. But not episode three, because Valve would rather make hats for people with fat wallets and short attention spans.
I'm not sure how this would work in the current gameplay system, as a key factor in the progression is "Kill Oro, and go back to normal, only a little bit stronger"
So, three years later, and let's see how our responses are different. For one thing, I said "bish" way more often than I would've liked. Also, I'd like to change my answer to telekenesis.