Elena's day at the beach was very well written.
I've been playing a Layla route for the sole purpose of getting closer to Elena, and it looks like we will soon be getting that branching path started. Probably not at the upcoming hot tub party, but maybe a scene or two after that. They both like each other, have serious chemistry with one another, and other people are starting to notice it. All of these things can be seen during the latest time at the beach with Elena.
But the one thing I really want to put a spotlight on are the inside jokes that Elena and the MC have going on. The beach scene begins with a with a minor misunderstanding that leads to a classic "Dios mio!" from Elena, due to the MC calling her mama because he misheard puppy as papi. The trip to the beach ends with the main character again calling her mama, and Elena laughing as she begs him not to call her that. To which he replies "No promises!"
This might seem like a very minor thing, but it's part of a larger pattern of ongoing gags and callbacks that show how the two are slowly building a relationship of their own away from Layla. For example, Elena will make a comment during the beach scene about the MC's "blood rushing to his head", which was a call back to the spiderman kiss scene where Layla didn't understand his attempt at a joke while Elena did. We also get the boys chanting "Elena has a boyfriend", which was previously made into an inside joke on the bus when he started to sing it to make Elena laugh, when she then had to explain the joke to Layla who had taken it literally.
The beach scene also had a bit of Japanese dialogue as he plays with the boys, which is a call back of sorts to when they were teasing Layla about writing Sayonara on her Spanish exam, which had resulted Elena tackling Layla to the ground in a bit of play wrestling, and us jumping on top to help Elena. Elena mentions that scene during their time at the beach as a time where she had previously noticed his "blood rushing to his head". That wrestling scene also had a moment where the MC fell on top of Elena and she says "You really like laying on top of me, huh?" which ties in perfectly with the beach blanket prank.
We also get the MC pretending to be heartbroken as Elena jokingly calls him a pretty boy, which she had previously mentioned as not her type of guy, which had caused the MC to say that pretty boys are the worst, leading Elena to say "So, pretty boys are the worst. Spending time with me is the second worst. I'm learning so much about you today." That was a reference to their earlier conversation when Elena had suggest they call it a day so she could go home and watch her brothers.
MC: Already? You don't want to stay a bit longer?
Elena: I want to, but now I have to look after my brothers and...
MC: You can do that here! I'll help you out. And I think they'd like to stay longer too and play a bit.
Elena: You sure you don't mind?
MC: I don't. And spending time with you isn't the worst either.
Elena: Not the worst, but the second worst?
MC: Second worst is not the worst!
Elena: Haha. Idiota!
These callbacks to previous jokes not only show that they have a shared sense of humour, but that they pay attention to what the other says and care enough to remember it. We can also see a level of respect for one another in conversations like the one where the main character wants to ask Elena if she has a boyfriend. He doesn't want to pry into her personal life, so he asks if he can ask a question. Elena jokingly says no. And the main character doesn't ask. This contrasts with how Migel and Zach would often overstep with the girls in their attempt to get to closer to them. Elena is curious about what the MC wanted to know and asks him what he was going to say.
Another example of how their time together at the beach shows good chemistry is how quickly they recover from the main character putting his foot in his mouth by making a comment about how Elena wears a lot of Layla's old clothes. Elena doesn't get defensive or insulted, but is embarrassed enough that she can't quite hide it (even though she tries). He picks up on this instantly and digs himself out of that hole quickly with a couple of compliments, which she recognizes as him understanding he made a mistake and that he didn't have any negative intentions. This ability for them to smooth over mistakes and fix them quickly bodes well for their future, and is again in stark contrast to how someone like Zach will unintentionally do things to annoy/upset Valeria and remain oblivious to it (which make him keep repeating the same mistakes).
So the point I'm trying to make here is that there is clearly a great amount of effort going into developing the relationship between Elena and the MC. It shows how Elena sees the MC as a being different from the average guys at school, and it is slowly setting up a branching path where the MC realizes that he's got more chemistry with Elena than with Layla. I'm betting that the MC will call Elena "mama" at some point during the hot tub party, and Layla will once again feel out of the loop as she has to get the joke explained to her.
I would say that this relationship has the best laid foundation of any in the game. It's developing in a natural and believable way, and the only concern I have is how soon we will be able to start to drift away from Layla without locking ourselves out of Elena's path.