A commenter to one of my earlier L/N posts asked what N-Score I would give Tetris. It is an interesting question and one I considered myself when I first began thinking about L/N.
To begin with, the N-Score would depend on the specific version of Tetris being reviewed. Any version of Tetris with a decent soundtrack and nice, crunchy sound effects would score somewhere in the average range of 9 to 12. A lack of, or low quality, sound effects or music could bring the N-Score below average while a truly excellent soundscape could pull it a little above average. Remember, I score games relative to their concept, so a complex narrative isn't a requirement for a puzzle game like Tetris. However, there are a number of things that a Tetris game could do to earn a significantly better than average N-Score.
For one, a dynamic soundtrack could do a lot to improve the "narrative experience" of Tetris. If the music matched the state of your current game, whether frantic and tense as you play on the knife's edge of defeat or triumphal and celebratory after landing a well set up tetris, you would certainly be more immersed in the game.
A Tetris game could also take a few cues from mahjong games and add opponents or antagonists that you play against. Instead of pieces dropping without explanation from the top of the screen, they could be positioned and dropped by an animated character. Tougher opponents would drop them faster and with different algorithms.
A Tetris game which did both of these could potentially earn a very high N-Score. So really, high N-Scores are not limited to certain narrative centric genres. Any game which maximizes the artistic and narrative potential of its concept can earn a high N-Score.