MIT Mystery Hunt 2020/Tunnel of Love

Tunnel of Love is an interactive audio puzzle from the round of the 2020 MIT Mystery Hunt. It [INSERT BRIEF DESCRIPTION]

Puzzle Elements
Interactive - The puzzle is contained in an applet. After clicking, the solver first hears a message "Hey everyone! Let's play hide 'n' seek!" before being allowed to wander through an area full of numbered rooms.

Flavortext - ''What a rip-off—this isn’t a tunnel, it’s just a giant, dark, empty room. And if these weird noises are supposed to be Romantic music, then I’d say they’re a little off. I wonder how these sounds got from wherever they should be to where they ended up, anyway.''

Hint in Flavortext - ''What a rip-off—this isn’t a tunnel, it’s just a giant, dark, empty room. And if these weird noises are supposed to be Romantic music, then I’d say they’re a little off. I wonder how these sounds got from wherever they should be to where they ended up, anyway.''

Audio - Across all 104 rooms, some will play sounds—the most common of these is the sound of a bell, while each other sound occurs exactly once.

Classical Music - Each sound is a clue to the nickname of one of Haydn's 104 Symphonies (as confirmed by the number of rooms, the reference in the flavortext about it being a little off Romantic music, and the "hide 'n' seek" pun)...

Enumeration - ...which can be filled into the enumeration blanks below the applet. ...

Marked Spaces - Some of the blanks have a circled number instead; taking those letters in numerical order gives...

Numberlink (Word Length) - ...DO NUMBERLINK. Each Symphony has two rooms associated with it—its actual number, and the number its corresponding sound was found in. Room 28, for example, contains the famous "The Surprise"... which is actually Symphony No. 94. Solving it as a raw numberlink, however, yields multiple solutions; the key insight is that the twelve symphonies represented together have 104 letters, so the number of squares each link passes through is equal to the length of the corresponding nickname. As clued by the flavortext, we should write the nickname along the links starting from the actual symphony number.

Marked Spaces - Extracting the letters from the rooms containing bells...

Reordering - ...and ordering by increasing symphony number yields the answer.