That's a good point; I actually had that thought later. (Since "Lust drauf?" omits "Hast du", and "Feel like it?" omits "Do you"--they're very parallel.) It is a better translation. But, given that the stated intention here is to teach German (and not necessarily just to native English speakers, presumably?), I disagree with counting "Do you feel like it?" wrong, because it fully captures the meaning, in perfect English.