As a songwriter:

Nathaniel was constantly revisiting the music of Overtime, honing every beat and note with both the band and cast. The result was an extremely precise score, that was complex, ambitious, and full of heart.
— Myle Yan Tay, playwright of Overtime.
Speaking of numbers, Nathaniel Mah’s score is expertly composed and wide-ranging, spanning genres from rap (‘Scene One’) to stripped down, acoustic guitar (‘Found’), every song appropriately capturing the mood in their scenes. Mah also often utilizes refrains and reprises like a professional musical composer, and he would do well to continue down a similar path in future with this kind of promise.
— Bakchormeeboy.

(See Bakchormeeboy's full review of Overtime here.)

As a producer:

As a professional, Nathaniel is dedicated and straightforward, putting in the necessary time to make sure the recording and mixes were always of top quality, and facilitating a conducive channel of communication where we were able to openly critique and push each other to be better. Despite rap and hip-hop music not being his go-to genre, Nathaniel really pulled from his experience in musical score composition to bring a new flavour and set of ears to this project; his humility, open-mindedness, and commitment to provide the best sound really makes working with him a smooth and enjoyable experience.
— Subhas.