It was interesting to read your creative planning process as a team and how those plans came to fruition!
Love the soft guitar in "Port Corella!" "Sunny Beachside Town" definitely has a summer vibe to it - the two note high guitar phrases that sort of echo the first two notes of the lead instrument do a lot to support that. Man, the reverb on that bass is thick a f but it works pretty well here I feel.
"Starry Beachside Town" takes that guitar phrase I referenced earlier and immediately repurposes it into the main theme - love that! This song is kind of a slow-jam in comparison to the last track, and definitely gives me that night-time vibe.
You started cooking on "The Mystery of Base Corella" - this track is a hard right turn from where we started. I chuckled at the "couldn't hold myself back" in regards to the theremin. It is indeed gratuitous, but in the BEST kind of way, I assure you. The breakbeats toward the middle of "Unseen Threat" are a really nice touch that add to the mood pretty well. My only problem with this track is the majority of it feels so similar to the last one that it feels like it doesn't hold a lot of purpose or weight in the album as a whole. If you wanted to leave it as is for reference purposes, I might've suggested adding it as a bonus track at the end. Otherwise, some octave or instrument changes could have help to set this track apart.
"I Won't Forget You" changes the tone of "Oh... thats what happened" in a way that immediately builds some different emotions - though this feels a little more tense/anxious than reminiscent/nostalgic/etc to me.
"By The Pier" is a nice callback to the themes in the first part of the album, and once again brings my brain to this one specific song: https://www.google.com/search?client=firefox-b-1-d&q=outrun+splash+wave+pso2#fps... (which was used as a summer event theme in PSO 2,) mainly because of the similar summer vibe and the riff that comes in around 1:40. That is to say, you definitely nailed the sounds of summer as this track is the first thing that comes to mind when I think of beaches, volleyball, and ridiculous looking characters doing flips in the air while dual wielding laser guns (that last bit might be a bit more of PSO 2's fault, on second thought)
Anyway, got a little off-base there, but "By The Pier" was my favorite, and I appreciated the little drum and bass breakdown just pass the midpoint of the song. Overall, solid, solid album submission that was quite enjoyable to listen to. Great work!