Background: 700 years ago there was a mystical apocalypse that wiped out the vast empires of the day. What's left now are a series of city-states, trying to survive and expand in the aftermath. The PCs are members of a troubleshooting team sent out of the city to deal with threats, like monsters rampaging through the farms, make daring rescues, and explore the surrounding wilderness. So there's structure to the sandbox exploration -- for the good of the city-state.
Rules: The rules have been distilled down the the following traits: Combat Bonues (melee attack and damage, ranged attack and damage, and saving throw), Acrobatic Skill Bonuses (thieving skills), Armor (they use Ascending Armor Class), and Points (hits, mana, and experience). Starting PCs start with 10 trait points. You can optionally add the typical Attributes of OD&D (STR, DEX, CON, INT, WIS, CHA), but only for compatibility with other D&D systems and modules. Lost Empires also eliminates levels, allowing the player to add 1 to one of their character's Bonuses or Points every 1000 experience points. Essentially, the rules are a simple point-based character system.
Example PCs: Here is a sample warrior from the book.
Wenst, Elvish Warrior
Profile: Knight with woodland skill who is always eager to rush into battle.
- Melee Attack: 2
- Melee Damage: 2
- Ranged Attack: 0
- Ranged Damage: 0
- Saving Throw: 0
- Hit Points: 6
- Experience Points: 0
Combat entails rolling a d20, adding the appropriate combat bonus (melee or ranged), and if you beat the armor class of the opponent, you hit. The rules also have open-ended effect rolls (damage, spellcasting, etc.) called Bullseye Rolls. If you roll maximum damage for the damage die (e.g. 8 on a d8), you can roll another die and add it. Repeat until you don't roll the max.
If a player rolls a bullseye, they gain d6 Feat Points. Feat points can be spent on various effects, such as healing, attack advantages, mana recovery, magical effects, or acrobatic maneuvers.
Spellcasting is very interesting. Mages have Mana Points. Spells are not memorized, and any mage can attempt any spell. But if the mana cost to cast a spell exceeds their remaining mana (known as 'overcasting'), the mage takes any remaining cost as physical damage, potentially killing the mage. Spells are rated by what die you roll for the mana cost. For instance, Sleep is a d4 spell, Remove Curse is d12, and Light is a 1-mana Cantrip. The spell cost roll can also bullseye, potentially making the spellcasting very expensive and dangerous.
Spellcasting Example: Here is a spellcasting sample from the book.
Dagu, a mage, has only 16 mana points available, but is in a pinch so he attempts a d20 spell. He rolls a 20, which is a bullseye, rolls again and gets a 5. The spell takes effect but costs 25 mana. Dagu had only 16 mana available, so all 16 mana points are spent, and the remaining 9 "overcast" mana points deal 9 damage. The bullseye roll means Dagu gained a feat, so he rolls a d6; perhaps the feat will be worth the extra damage.
The rules comprise 16 pages of the 60-page book, with the rest taken up by the Spell Book, GM's Guide, and the Bestiary.
I haven't played it, but I might make some PCs and try some solo adventuring to test it out. I really want to use the background, perhaps with these rules or maybe GURPS Lite or TFT.