Powell took a different course on The Goon when he wrote this one. Not only wasn't it published as part of the ongoing comic, coming out as a stand alone graphic novel instead, it's also not nearly as humorous as the comic. Oh, sure, there's still some humor. Frankie's in it, after all. You can hardly have Frakie appear without some mirth.
That's the thumbnail, but there's so much to the development of the characters that Powell brings to this divergent story that even though the plot isn't a part of what was happening in the comic at the time, it's clearly important to the participants in the comic. Oh, and a dragon is introduced to the mythos of The Goon. That's pretty cool, right? Besides, there are nods to Casablanca, To Have and Have Not, and, of course, Chinatown, which are not to be missed.
The bonus in this trade is at the back of the book. Powell provides some sketches of the work and, more importantly, some explanation of his thinking in the process and the plotting. It's a very nice insight into his creative process. Powell is frank about his own doubts about where he was going with the project and the time off from the comic that he was taking to do it. It certainly wasn't the usual path taken by a creator, and the faith Dark Horse had in him going this route is pretty impressive for a business that usually wants a regular supply of its product available for its customers.
This book is widely celebrated for good reason.