Mangayaw is a serious and substantial Cairn-based adventure rpg.
The PDF is 30 pages with a clean, well-organized layout and some nice atmospheric illustrations. The cover in particular is super evocative and fun, and it's a great tone-setter for the osr feel of the book.
Contents wise, Mangayaw's setting is based on the colonial era of the Phillipines. Players work together to navigate a hostile and supernatural chain of islands, torn by factional conflict and invaders.
In terms of support for the GM and players, there's a *lot.* There's detailed guides on how to play the game, what to expect, the designer's intentions, safety tools, and it's all frontloaded. There's also a robust guide to the setting---its factions and cultures and metaphysics---and a corresponding bestiary.
The game wants to feel lethal and meaningful, with no character being invincible, and no character particularly wanting to die. And it definitely achieves this goal. It also feels a grim and messy, as appropriate for any colonial era.
By default it deals with heavy themes that it doesn't want to handwave as 'just part of adventuring.'
Mechanically, Mangayaw's engine is going to feel pretty familiar to anyone who's played osr before. You have three stats to roll on, rations and resources to track, ancestries and backgrounds, armor and magic.
However, there's a little more complexity here than something like Into The Odd. Weapons have a lot of potential traits that change how they function, giving everything its own niche. Ships are important for travel between islands, and have their own detailed statlines. Inventory is capped at 10, and there are status effects such as Fatigue that can block those slots Mausritter style.
Combat cares about positioning, and features AoE attacks---although most attacks will be of the standard single target roll to hit variety. Combat also revolves around relatively low amounts of HP that's easy to recover, and there's lasting changes to your character if you take lethal damage and survive.
Magic uses a neat keyword system, where each keyword has a set of spells associated with it and once you've learned all of them you can develop new spells. Casting spells is powerful---it just works---but the tradeoff is that it imposes status effects on you, such as the Fatigue mentioned above.
Non-casting characters can use mentala, anting-anting, oils, and other consumables to get spell-like effects without needing to carry a sorcerer around. These are part of an extensive list of equipment that the book provides, and they're all varied and flavorful.
Mangayaw's game-loop isn't purely focused on adventuring, and there are mechanics for building and upgrading a community. There's also rules for followers, foraging, hexcrawling, and quite a bit of strategic meat on the lightweight system.
Overall, if you're looking for a serious-toned fantasy adventure game with osr sensibilities, that's easy to learn and teach, and that has a really solid structure, this should be in your game library. It's got a ton of content. Everything in it is clearly explained. And it feels more grounded than fanciful. If anything I've said here interests you, check it out.