Hey!

I just looked through the technology tree and found the following:
--> In order to unlock blue algae "Cement processing 2" is required.
--> Cement processing 2 requires blue science.
--> In order to create blue science plastics/oil is needed
--> Plastics/oil are created from blue algae.

In other words; the "cement processing 2" is blocking the progress. It doesn't seem necessary at that stage either.

Thanks for the report.
fixed in 2.1.6.

a recent Angel's update added Cement processing 2 and Aluminium smelting 1 as prerequisites of Blue algae processing.
In Angel's they're needed for Algae farm 4, which that tech unlocks there.

Sea Block unlocks Algae farm 4 later, through Advanced algae processing, so the prerequisites only blocked blue algae.
Since blue algae is Sea Block's only crude oil source, oil processing and everything after it were stuck behind blue science, even though none of those techs cost blue science packs.

Blue algae processing now only needs green science again.
Aluminium smelting 1 moved to Advanced algae processing, where Algae farm 4 actually needs it.

One small correction: it wasn't a hard soft-lock. In this pack, advanced circuits don't use plastic, so blue science could still be crafted without oil. It was still clearly the wrong progression though, so thanks again for catching it

Big thanks for the quick response and fix!

It has been smooth sailing so far and the early changes feel natural :) Thanks for updating/reviving this awesome mod!

You're welcome