Yeah HK is a gem, but it's hard to create something approaching in a RPG ! My version was more levily, "before the fall" in a way, 'cause you can interact more easily with the world, NPCs and all. I'm not totally sure it would be easys to make an empty world with lore written on objects and still be interesting ôo
A few games to recreate that, at the top of my head :
You can check out UMBRA. It's a HK-ttrpg inspired and based on the LUMEN system, so fast paced combat. I'm not totally fond of how in this one they used states and well, since it's focused on combat, the exploration part is very thin. But it was a fun basis for us.
UMBRA by Star Bear Games (itch.io)
I've seen the game Fireflight was out recently, which tries to emulate the metroidvania genre and with some souls-borne loneliness I guess.
There's a SRD to hack it !
Firelights by Fari RPGs (René-Pier Deshaies) (itch.io)
There's DiceSouls, which have some neat mechanic to connect zones and explore the world ! And a good trick to recreate the "I've died against this enenmy, I'll be better next time"
Dice Souls by Chris Bissette (itch.io)
Maybe RUNE, which is really a light-tactictal combat in Solo (No GM), and exploration on a map. It's not very HK, but there's some game design bits to steal I'm sure ^^
RUNE by Gila RPGs (itch.io)