SPOILER!!! ------- Killed the giant worm thing in the Enroachment cave. What now?

[Princz]

Killed the worm / placed the small blue thing in place / big blue thing glows now / What now??

Achivement suggests that there should be more to do here.

"There may yet be more to explore" (Coreverse achievement)

[Nerevar]

thats it for now. there is only the worm merchant in the backcave but you need the suit to interact with him.

[@xaker89]

This is just a small crossover with the game called Core keeper, so there is not that much stuff in there.

[Doctor Darling]

Yup. Once you power up the core, that's it with it. It's basically how you gotta defeat the first three bosses in Core Keeper to power the Core in that game.