Some changes from the first game are that ink rails can be grinded upon; similar to how Sonic the Hedgehog does, as well as being able to be used in squid form like before. (cultureofgaming.com)
If you turn into squid form while holding a full charge, you can maintain the charged state briefly while moving around. (gonintendo.com)
When squid form Inklings are on dry land they are only able to slither slowly, even slower than a humanoid Inkling. (splatoonwiki.org)