There are so many things a player could do to make the game harder:
No Armor/naked runs
Only green weapons
Stay at level 1, Never level up
Never long rest
Make your main stat your dump stat (e.g.: barbarians/fighters, make your strength 8; wizards make your intelligence 8; bards make your charisma 8; rogues make your dex 8)
Wear armor and use weapons your character is not proficient in, giving yourself disadvantage
I'm impressed by this playthrough:
^ Complete the entire game on Tactician mode, with a level 1 party.
