This is your typical cliffhanger adventure serial of the time. Sneering bad guys, daring heroes, exotic locations, and a fun over-the-top plot.
This was the pulpy fiction of men's magazines brought to life (with much less sex and violence, considering the censors). And while it lasts, it's a fun watch.
There are a couple things that make this one notable, though.
One is the casting of Charlie Chan's Number One Son and Asian American acting pioneer Key Luke as one of the good guys working undercover in a hotel. As usual, he gives a good performance and it's just nice to see him acting, especially in a time where most non-white faces were just background characters. Here Luke plays a role and is involved in the plot, not just a servant or something similar.
The second is that this production had to overcome the sudden death of Lionel Atwill, one of its named stars, during production.
Some clever editing and reshoots were done, lessening Atwill's role, installing his character's secretary as main villain, and using stock footage and disguises to finish the story. It is an inventive way to overcome the death of one of your main actors, but the seems do show occasionally, and it also shows how callous studios were at the time.
The film also makes use of stock footage a lot to overcome budget limitations, but it's edited into everything well enough that you'll only notice if you look for it.
As a science fiction adventure writer who loves pulp novels and writes them himself, this is a grand bit of research into an era of silly cinema that we just don't really get anymore.
Well worth a watch if you find a decent copy!