First, let me declare up front that OSIRIS isn't a game for me. It just doesn't push any of my buttons and doesn't do anything I couldn't do in any of a dozen other systems. That doesn't mean it's a bad game or it wouldn't match the play style that you and your group enjoy. So, keep this caveat in mind while reading this review.

The book itself is a 195 page, full color, watermarked PDF weighing in at 33.7 MB. The artwork is good quality, some pieces much better than others, but all of them do a pretty good job of matching the context they appear in. The pictures of weapons and armor are some of the best and most illustrative of the things being described. The layout looks professional, and I didn't spot any obvious typo's or spelling errors. Overall, OSIRIS gets good marks as a professionally presented game book, though the tone in places is more conversational or even casual.

"Osiris is not geared towards a particular game setting or style of play, but is general enough to work in almost any situation." (pg. 2)

I don't agree with this statement. In my opinion the rules strongly influence a very specific style of play. While there's nothing wrong with that style of play, there's also nothing outrageously different about it either. If you're looking for a game that does things differently, then this may well be your game. If you're looking for a game that does different things, then this is probably not going to scratch that itch.

OSIRIS is presented as a generic RPG, in that it can be used for fantasy or sci-fi and does not have a specific setting attached, but can be adapted to one of your own devising. This is reenforced by having items in the equipment, weapons, armor, and skill lists that draw from many different genre's and could easily be used to inform custom additions by the GM.

The introduction chapter has a lot of information about "What is role-playing?" which leans heavily on the opinion of the author. It also includes (on page 8) "What isn't role-playing?" where the author advocates that table-top RPG's "get away from crunchy numbers" and that it should be more like "improv acting with a bit more focus." Again, that may or may not be how you approach gaming, but in any case, I don't entirely agree that OSIRIS isn't crunchy. As you'll see in the description, there's a lot of detailed rules for many, many situations. There are entirely different sub-systems (such as Combat Skills vs Field Skills vs Trade Skills). There is a non-optional requirement to use hit locations, both in creating characters and in combat. That may not be seen as 'crunchy' by the author, or by you, but it's crunchier than a lot of new style games and certainly would not make many "rules lite" or "low crunch" gaming lists.

Here's a summary of the rules system.

Characters have eight abilities in four categories. The categories are Physical, Emotional, Mental, and Spiritual. The two physical abilities are Strength and Fitness, the two emotional abilities are Clarity and Depth, the two mental abilities are Intellect and Wit, the two spiritual abilities are Magnetism and Connection. You generate their scores by rolling 5d10 and dropping the lowest die. Assign the remaining four dice to each category. You can move up to two points between categories. Now, assign the category value to each ability in that category. For example, if Physical had a score of 2 then both Strength and Fitness would get scores of 2. Now you're allowed to move up to two points between each ability, within each category. So in the example, you could drop Strength to 1 and boost Fitness to 3 by moving 1 point between them. When you're done with this, you have values in all eight abilities. Now you calculate your three endurance scores: Wound Points, Stamina Points, and Mana Points. These are the sum of two abilities, for example Wound Points are Strength + Fitness.

I find this part of character creation to be needlessly fiddly, but pretty easy to follow. The caveat, is that you won't know what abilities to boost until you know how the rest of the system works and what kind of character you'd like to play. At least some measure of system mastery is rewarded by OSIRIS, and knowing how to get the kind of character you want with the rolled abilities is part of that.

There is also a brief description of how combat affects the endurance scores. Damage is first applied against Stamina until it is exhausted (reduced to zero) and then it's applied against Wounds, representing real damage and scars to the character. If Wounds reach zero, then the character is incapacitated or killed; the rules seem to leave this to the narrative control of the GM. It is possible to score a critical hit on a natural 20, which causes special critical damage to bypass armor and stamina and be applied directly to Wounds. I actually like this idea, and each weapon has a "critical damage die" which is applied when a critical hit happens.

Heroic Powers (covered later in the book) cost Stamina to use while Spells cost Mana to use.

Next Combat Skills are described. There are eight combat skills that are each tracked separately for each character. Their starting values are based on the ability scores, but they are increased independently after character creation. Each combat skill comes as a matched set, an Attack and a Defense: Melee Attack, Melee Defense, Ranged Attack, Ranged Defense, Magical Attack, Magical Defense, Psychic Attack, Psychic Defense.

Finally you calculate two "Reaction Skills," Reflex and Will. Like the endurance skills, these start as the sum of two abilities.

Combat is resolved as an opposed roll of the attackers Attack skill + situational modifiers + d20 vs the defenders Defense skill + situational modifiers + d20. If the attack roll is equal to or greater than the defense roll, it's a hit, otherwise a miss. If the attacker hits, then damage is rolled (d4, d6, d8, d10, d12, etc.), the defenders armor (if any) is subtracted, and the remainder is applied to Stamina (or if Stamina is zero, applied to Wounds).

This system is pretty easy to understand, and situational modifiers are just simple addition or subtraction for things like footing, cover, etc.

Initiative is a little more convoluted, in that it's a Reflex + d20 and if the resulting roll is high enough the character can act multiple times in each combat round. But, these bonus actions can't do as many things as a regular action. In any case, there's a simple table on page 29 that shows how many attacks per round based on the Reflex roll result.

Proficiencies can be added as characters earn experience, these are combat skills that give a small bonus to very specific combat actions or a single type of weapon.

Chapter 3 is for equipment, which is rated in tech levels from Primitive to Future tech. Page 47 specifically eschews encumbrance, though armor does have a "Bulk Penalty" rating which is applied to the characters Reflex roll in combat (i.e. characters act later in a combat round if they are wearing bulky or heavy armor). Weapons get a Speed rating which either adds to or subtracts from the Reflex roll. This is to reflect the difference in wielding a rapier versus a pole-arm. Weapons also have a Breaking Odds score, which is a d100 roll-under whenever the player rolls a natural 1 on a d20. It's the chance that a weapon will break on a critical failure.

The weapons and armor cover a wide gamut from slings and bows to plasma swords and hand grenades. While there is a description of how to include magic items, such as magic weapons and armor, they are not listed or detailed; this may be covered in a future supplement.

The next type of skills described are "Field Skills" which are meant to literally be skills useful in the field. Examples include Awareness, Climb, and Disguise. The pool of points that can be spent on Field Skills is based on Intellect and the characters age. The base skill check is Field Skill + d20.

Then there are Trade Skills, which are for making things, having special knowledge, or earning a living. Examples include Architect, Armorer, Blacksmith, and Carpenter. These skills are used with a d100 roll under system, unlike any of the others.

OSIRIS also includes Heroic Powers which are something like feats in other systems. They give special bonuses in specific situations, cost Stamina to use, and are not available to starting characters but must be purchased as characters progress. Some of the Heroic Powers have comedic names like "Shazbot!" ("Whatever badass move it was that you just did, this power guarantees that a video of it, no matter how unlikely, will show up on the internet within 24 hours... even if its just some fuzzy security cam footage.") and "Rrrrowwr!" ("You are so hot that when you strut your stuff people sweat.") Obviously they need to be tuned for the particular setting, but they can add a lot of color and uniqueness to a character.

Character advancement is handled in a hybrid point-buy / leveling system. Characters earn Adventure Points during play, and every 20 Adventure Points can "level up." If the player is new to OSIRIS or new to RPG's, then the author encourages them to just choose one of the predefined "leveling templates" which are basically a set way to distribute the 20 points just earned. There are four templates in the book (Warrior, Mage, Priest, and Rogue) but nothing prevents the GM from creating others. If the player is more comfortable with the system, they may skip the template and assign the points piecemeal, as they choose.

Chapter 6 describes character races, and actually does a very good job of describing how to build a racial template with a list of abilities like low-light vision, keen hearing, predatory scent, etc. Then it details a list of "standard character races" which are all playable.

• Human
• Cao ("A cao is essentially a sentient feline roughly the size of a bus, with four ears, four wings, and two tails.")
• Dover ("Dovers are noble canine humanoids with a love for nature.")
• Dwarf
• High Elf
• Woodland Elf
• Frey ("The Frey are a race of upright felines that strongly resemble domestic cats in their morphology, only with opposable thumbs.")
• Haze ("Haze are stout, heavily-muscled, noble warriors, and are well- renowned for their loyalty, adherence to rules, and their prowess in combat.")
• Nightling (Large, muscular, lizard-like creatures known for being lazy and parasitic.)
• Picker ("Pickers are roguish little reptiles with a strong affinity for collecting and appraising interesting items.")

I don't know how "standard" half of those would really be, but it does demonstrate how to put together a racial template and there are good guidelines on page 124 for a GM to construct their own for the kind of game they want to run.

Chapter 9 is about magic, and how it works. In OSIRIS, magic requires five things:

• Natural Gifts; certain minimum ability scores
• Magical Affinity; bloodline, forbidden tome, astrological convergence, etc.
• Mana Points; these are an endurance attribute calculated during character creation
• Spell Books; a school of magic, a particular domain of spells, there are prereq's for obtaining a spell book
• Spells; a specific magical action, powered by Mana Points (Heroic Actions, on the other hand, are powered by Stamina points)

Except that "Spell Books" need not be actual, physical books. They may be schools or domains of magic.

There are a few paragraphs about Psionics, but they are not detailed in this book, with a promise to cover them in a future supplement.

Chapter 10 is about environmental hazards like falling, drowning, pressure, vacuum, fire, heat, cold, storms, etc.

Finally, chapter 11 is titled "Role-Playing 620." I don't know why it's called "Role-Playing 620" and I can't find an explanation for the "620" part; the most likely reference in Urban Dictionary doesn't make a lot of sense in this context. This chapter is the authors personal idea of role-playing, why it's fun, why it's important, and how best to play it. You may or may not agree and in any case, it's probably best that it was at the end of the book.

In conclusion, OSIRIS seems like a fully playable "fantasy heart breaker" in the traditional style of table-top RPG's. I'm a little dubious about how well the system works in non-fantasy settings (despite the expansive equipment section) because magic is integral to the character in the form of two abilities, one endurance score, and two combat skills! I also feel that the detailed combat rules with weapon speed, armor bulk penalty, multiple attacks per round, and required hit location rolls / damage make this system crunchier than I'm comfortable with. But that's me; OSIRIS may be exactly what you're looking for. Many groups want the more detailed combat rules, and OSIRIS does a good job of providing them in an easy to understand format. It's a nicely laid out, and except for no magical items or psionics, a fairly complete core rule book for $10. If it matches your gaming style then it's worth taking a look at.