The PC section has tips for creating characters based on the major archetypes. Despite leaning toward a faithful representation of the pulp genre (acknowledging, without trying to sanitize or replace, all the racism and sexism that entails), the book makes it clear that capable female "heroines" are definitely in-genre. The advantages/disadvantages and equipment lists are okay.

The GM section is much poorer. Most of the advice seems geared toward writing pulp fiction, instead of recreating the tropes in a game. And even when it's game related, it's never fleshed out (Underhill suggests handing out wallets full of receipts, identification, and so on as a prop -- which is a good idea, but he never says what kinds of papers are common in the 1930s, or what receipts from that era look like).

While focused on the heroic pulps, the book seems to shy from the larger-than-life aspects. Characters are assumed to be built on the third edition GURPS default of 100 points (with perhaps a mentor at 250 points), which just isn't enough to replicate someone like Doc Savage. The gadgeteering rules seems more geared toward making flashlights a couple of tech levels early, instead of fantastic alt-science like phlogiston generators. Overall it's not bad, but mechanically it's too rooted in GURPS' more gritty, realistic conventions to properly capture the high-flying action of the genre Cliffhangers attempts to emulate.