>>719754648
Marked secret: weird texture
Metroid 2 Return of Samus has less repeated rooms, but still use that concept for secrets. One example is the Chozo statue which always has a bottom tunnel.
It also introduced "weird tiles" to hint for secret passages. Probably due to its limited graphical capabilities, those are pretty bad and are used sparingly, mostly at the beginning of the game to teach the player to look for pass-trough walls.