[rowinofwin]

In a lot of cases as your planet size goes up the gravity doesn't go up as fast at the surface as you would expect. First off, sometimes the density is different, so you would have a similar sized but lighter planet. Other times it would just be the distance from the mass meaning that the mass on the opposite side of the planet has less effect than you would expect at the surface. If you add extra mass you also increase the radioactive decay potential which is part of our core being warm. More radioactive material, a longer time with a stronger magnetic field, less damage from solar radiation. And yes, the surface fluid being denser would provide more boyancy, so an aquatic species would have less of an issue from multiple times Earth gravity.

Pretty cool stuff.