How to play fifth edition D&D old school style:
Character gen like this
8 hour rests to get spells/abilities back
Group initiative (each side rolls a d6)
Old school healing + Death & Dismemberment
"Concentration" spells sometimes require literal concentration--depends on the spell. It's not just "you need to be awake", sometimes you won't be able to do other stuff.
Starting at 5th level non-casting classes and monsters add their naked d20 to-hit roll to damage (to counter Caster supremacy once fireballs kick in)
Monsters are custom-built when the players are over 5th high level, the monsters roll d20s and d30s for damage.
Rangers like this
Paladins like this
Witch/Warlock like this
Clerics like this
...ideally I'd like to rewrite all the classes and spells and so not have to do the +d20-kludge, but this works for now better than any other game so there we go.
d100 Hazards for old mine tunnels
17 hours ago