Bayonetta the RPG is a conversion of the setting and characters of the Bayonetta series to the free rpg system Risus.
The PDF is 11 pages with a pretty simple layout. There's a hyperlinked table of contents which helps quite a bit with navigating, but a few spots (such as character creation and additional background) feel like walls of words on first glance.
As far as system choices go, Risus is a solid match for Bayo's style and tone. Risus is quick to pick up and crunchy enough to notice, and Bayo The RPG goes a step further by adding a few fun mechanics on top of Risus' normal engine.
Typically in Risus, you make up a few broad phrases to describe yourself, you invest some dice in each, and then you roll those traits to resolve checks. In Bayo RPG, you also have weapons (which add their dice alongside other traits,) quests (which have large pools but deplete over the course of the session,) and familiars (which are secondary characters with their own traits.) This gives the players a bit more freedom to engage mechanically with the game, and echoes the feeling of style and mastery you get from playing regular Bayonetta.
If you're not familiar with Risus, almost all of the core rules are covered here. I couldn't find an explanation for how damage worked, and skill check resolutions aren't perfectly spelled out. Likewise, there's a short primer on the Bayo lore at the start, but it doesn't quite communicate how nonsense the action can get. So if the setting or system is wholly new to you, you should probably check out some lets plays or download Risus before reading this.
Although the book doesn't strictly need it, GM tools are included and include a reasonably thorough bestiary as well as a quick equipment list (everything is just made of traits and dice pools,) plus a full scenario. The scenario is semi-competitive (the PCs are working against each other to win a contest) and might make for a good way to bring together a cast from wildly different backgrounds. It's also a bit goofy, and it leads straight into a hook for another adventure, so you may want to tweak the ending slightly if you're running it as a one-shot.
Ultimately, if you want to play an RPG set in the Bayonetta universe without having to build it yourself, and especially if you want a game the captures the loose, free-flowing feeling of Bayonetta, this is worth picking up.
If you're new to Bayo and want to learn the lore, or if you want a really high-crunch system, this may be less your thing, but it seems pretty moddable, so it's possibly worth checking out anyway.
Minor Issues:
-Page 4, are your invested dice refunded if your familiar dies?
-Page 5, A Note About Demonic Power, is the intent here that you can always narrate doing cool stuff with your power, and you only need to roll if it mechanically impacts the situation? The way this section is phrased makes the intent a little ambigious.