From the update notes:"- Optional energy turrets have been installed in some areas of the Jelly Farm 2."
Just to see what the heck he was talking about, I ran a Jelly Farm 2 level in T1.
These are apparently the "mecha turrets" from the preview (I think - didn't play the the preview, so couldn't tell for sure). They are automatic turrets, costing 5 energy to activate (versus the 3 from the preview according to the wiki). They will automatically target any enemy that gets within range, and have a fairly powerful laser weapon (they'll 1-hit jellies on T1, at least).
The real question here: why put them in Jelly Farm 2? Is there someone out there who has complained about that particular map being too hard?
So I've spent a few energy to find out what they are. But I'll never use them again, unless they appear somewhere where I actually need help surviving (like danger rooms or arenas).
File this "improvement" under "answering the question nobody asked".
They are quite helpful, and I agree, why the heck put them in one of the easiest places in the game? Put them in a danger room as said, arenas perhaps, or regular rooms.