For those familiar with 5ed D&D, here are some of the major changes I have made:
- Count-up Initiative: This is slightly different from what you are used to, but easy enough to teach quickly.
- Reduced Flanking Bonus: Flanking provides a flat +2 bonus to your attack roll. This stacks with any advantage you might gain.
- Extended Rest Times: As per the "Gritty Realism" rest variant on page 267 of the DMG, a short rest requires 8 hours and a long rest requires 7 days. (A long rest restores all HP and all Hit Dice.) Combat is dangerous and taxing. Avoiding violence should be your primary goal.
- Specific Beats Generic: This is more an operational philosophy, but it is worth noting. Things are hidden in specific places. Traps have exact triggers. If you describe a specific action, you can find the hidden thing, avoid the trap, and so on without any dice rolls. You can still use Perception tests to find things, but this puts you at the mercy of the dice.
- Level Zero: Your starting Hit Points is 4 + Constitution modifier. You have a single Hit Die of size D4. You have negative 100 XP. Once you "buy off" this debt, you become level 1 in the class of your choice. You lose your starting HP and Hit Dice and instead gain the starting HP and Hit Dice of the class.
- Experience Points: You will earn your levels with XP. Because killing monsters is not the focus of this game, you only get half XP rewards for defeating monsters. Your XP will be augmented with an achievement-based system. (Fulfill the requirements for an achievement and gain the XP.)
- Food, Water, and Sleep: You need one pound of food and one gallon of fluid per day. Failure inflicts one level of Exhaustion that cannot be removed until you eat and drink. You need six hours of sleep each night. To sleep, you must be dry, warm, and comfortable. If one of these things is missing, you can still get adequate rest with a DC 10 Constitution saving throw. If two of these things are missing, the test is at disadvantage. If all three are missing, restful sleep is impossible. Missing sleep gives you one level of Exhaustion and you cannot remove any levels of Exhaustion until you get adequate rest.