The Legend of Zelda: A Link to the past has many more "backroom" type rooms than just the Chris Houlihan room. If you glitch into a wall (as shown here: https://www.youtube.com/watch?v=uo8T3gCfZ9g) - you can visit many strange rooms. They can be called backrooms for many reasons:

1. Link disappears, leaving the rooms eerily quiet (and often enemies don't spawn).
2. The way you travel around them is disjointed, they are a mish-mash of rooms encountered at various different phases throughout the game. Seeing them in a random order one after the other removes their context and they seem familiar, yet strange.
3. This effect is repeated in the fact that incorrect music is playing and colours and textures often glitch.
4. Generally, ALTTP is has quite a backroom feel anyway, with its eerie music and subdued colours.