Brick House
Beginning the challenge, all we are given is a MysteryTape.wav.
What is this?
The challenge description mentions the 80s and โBasic Programs #1.โ, letโs see if we can identify what that might be!
Considering itโs the 80s, it is probably talking about some older computers that used tape. From a quick search these include the Commodore 64, Apple II and BBC Micro. I decided to pursue the Commodore 64 just because a lecturer had talked about it before :p (you know who you areโฆ)
The next step became, how can we emulate this?
Emulation
The first result is the Emulation Wiki where it suggests the โVICEโ emulator.
After installing VICE from SourceForge (I used the GTK3 version), the application boots with a delightfully dated UI:

Using the controls down the bottom, we can load tapes:

I try to load the MysteryTape.wav, but it doesnโt workโฆ
Converting to tap
With some research, I find VICE and most other emulators seem to use .tap files for tapes.
A program to convert a WAV to TAP is WAV-PRG.
Opening the program, we are met with another delightfully ancient UI:

I press โCreate a TAP fileโ and then โfrom an audio file (WAV or similar)โ and then โOKโ. Then I select the MysteryTape.wav.
After that, we get a MysteryTap.wav!
Emulation (again)
I attach the MysteryTap.tap with the โAutostartโ option and press Play.

Flag: DawgCTF{B4CK_70_B451C5}
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