Solid concept, reminds me of some PS2 puzzle platformers for some reason. Forgive the following battery of bug reports, these are some things I ran into during my time playing that I haven't seen anyone else mention here:

-Cthulu moves very slowly. It might make sense since he's so big, but I was left waiting for long stretches sometimes while I waited for him to catch up to where the fisherman was in the level.
-The collision on the physics props was a little wonky, pretty much every bridge I made by knocking a stone over shook itself apart as my character ran across it.
-I fell into the gap at the beginning before I understood I needed to make a bridge, and my character did not respawn at a checkpoint, requiring a restart.
-It wasn't obvious to me that I could control the cultists, an outline on them too might help.
-I died during the part with the pressure plates that released green gas, after already passing two pressure plates. The checkpoint placed me before the first one, and it seemed I couldn't get past it without activating it anymore.
-The hands were extra difficult to manipulate, it seemed like they would eat one of my inputs, and then there was a timer before I could interact with them again, at which point they would then work. That happened for every single hand, so every single hand had like a ~10 second wait tacked onto it
-There were a few puzzles that I solved by placing the fisherman on a box and carrying him to the finish with Cthulu (this is how I got past the green gas pressure plates). To be clear, I enjoyed this a lot, but it probably wasn't intended and could make some puzzles trivial.

Despite writing all these issues out in list format, my experience with the game was overall positive lol. Looking past the minor technical problems, the gameplay was good, the atmosphere was well constructed, and I had fun.

Oh, I really love Lovecraft books, so thank you for this game! Funny and athmospheric :)

Liked the idea and really atmospheric enviroment. Seeing Cthulhu model made it feel really imposing and in turn turn fisherman that much smaller feeling, so feeling of scale was felt. Some problems with playability, grabbing items and limited camera made playing itself bit frustrating, but I really liked the idea, look and feeling that I'm but a little speck in this cosmos. Great job :)

Good graphics and pretty good gameplay :)

Very cool idea,

 I that felt that the puzzles were quite simple, the difference in scale between when viewing through Cthulu's perspective is exceptional and I would recommend giving Cthulu an animation as he is currently completely still.