i was really impressed by this one! the presentation is really good, i love the submarine's art. and the music is nice too!
this game's take on the (...very popular) chain mechanic has some cool twists. i like how coins increase its length, it's almost kinda like a metroidvania in how you unlock new areas. it's also handy for backtracking and finding your way back from a long tunnel maze. AND it's relevant to the story of the game! cool stuff
i think the game gets pretty tedious at parts though, like when you have to keep going back and forth to collect coins or get boxes (or unwind your chain). if this game were expanded on, i'd try putting more obstacles in the way, and giving the player more options to traverse quickly. also, the box pull could have a dedicated button, instead of having to stand still for a long time
the other thing i really liked was the inclusion of things like dialogue and hidden trophies - pretty in-depth for a jam game! had a very good time with this as a proof-of-concept, and would like to see this take on the chain explored in a faster-paced title!