Basic Rules: Basic Rules: Use of the basic rules ensures 100% accessibility to the gaming table.
Ability Scores (pg. 9): Are generated with dice, as per the RAW.
Starting Wealth (pg. 45): Is rolled at 1st level. Starting equipment from your class is not used.
Encumbrance (pg. 63): Use the variant option.
Healer's Kit Dependency (DMG 266): Characters can only spend HD after a short rest if someone expends one use of a healer's kit to bandage their wounds.
Side Initiative (DMG 270): Each side rolls a d20 at the start of combat. Initiative is re-rolled at the start of each round.
Backgrounds: Are not used. You can write up a backstory for your character, but it wont have any mechanical effect. Character development emerges from play, thus happening at the table. Not away from it.
Fumbles If you roll a natural 1 on an attack, the next creature to take the attack action against you does so with advantage. F is for
Death Saves: One (and only one) save is made when combat is over. Other characters may attempt to stabilize the dying character by expending a use of a healer's kit to grant advantage on this roll. Combat is quick and deadly. This helps enforce the notion.
Resource Management: 1 ration and 1 filled waterskin is required for each day adventuring in the wilderness. Part of the wilderness adventuring phase will include finding a suitable place to camp. Camps provide adventurers with a clean water source to refill their skins. Exhaustion rules are strictly in effect. I love the 5e exhaustion rules. In my eyes, probably the most old-schol thing about the system.
Experience Points: Are gained by returning treasure found in the wilderness to the safety of civilization. Characters gain 1 XP for each GP brought back to town. Monsters only supply 1/10th of their listed XP values when slain. The goal is not to kill things, it's to be creative when in dangerous situations.
Setting: This is the big one. I'm not running a high fantasy game set in the Forgotten Realms. Instead, it's a frontier wilderness survival simulation. For the most part everything encountered in the wilderness is randomly generated. Town is considered safe all else is considered dangerous. Encounters are rolled randomly and are not balanced toward the player's level. That's not to say there won't be a story told...it's just not written ahead of time. It will emerge from play, not the other way around.