gandalf is on the right path there. The game uses Flash, so everyone with similar flash versions should get the same experience. That means on one machine, it shouldn't matter what browser you are using.
What can affect it is processor types. Different processors handle numbers differently - a number like this on a PC:
might show up as:
on a mac, and
on the iPhone.
In actual fact, the number SHOULD have been
but processors don't know how to handle such a big number.
(that is a super simplified version of the problem - look up Floating Point Problems in google if you want a more technical description)
When dealing with sensitive physics calculations, these small errors can start piling up more and more and more, and ultimately result in a contraption that wins on one machine, and doesn't win on another. Many contraptions will be behaving mathematically different, but not enough to actually cause a victory/no victory, but the more complex your contraption is the more likely it is to happen.