As earlier mentioned, mass does not affect the falling acceleration. That is, of course, unless air resistance or other outer forces applies to this game, which I'm pretty sure is not added (yet).
Also, this is a simulation of real-life experiments which happen at different frame rates, depending on the power of the computer playing toribash and the set limit of the game. Therefore, this can be considered as happening in slow-motion. There is no way to really measure gravity in this game as toribash doesn't reveal its measurement of time.