Do skills stack?

[Elzheiz]

If I buy the melee skills that makes your attack circular around you, then buy it again, is there any additional benefits like increased attack or something?

The above is just an example, I'm asking in a more general sense.

[Deventide]

In general all skills beside attack modifier skill nodes (like boomerang, swirl, revert shot or charge) stack. The latest update added a [Stackable] tag to ability skills which stack.

[Elzheiz]

Amazing :) I'll have a look then, thank you!