There is nothing to redeem — by design, not by neglect
A code list needs two things: a developer code system and working strings. HELLHOLE currently has neither, and pretending otherwise is how fake-code pages are born.
The developer, Game Chefs, has never published a code, and the game's menus contain no redemption screen. That makes HELLHOLE different from games with expired codes — there is no graveyard of dead strings here, just an ALPHA shooter whose rewards currently flow through daily login rewards (the 7 Days in Hell badge chain), loot chests, and gun mastery instead of promo codes.
This page stays at zero until the developer ships a redeem system. When that happens, every code listed here will name its reward and the date it was verified against this exact game — and codes that only appear in a YouTube title stay off the page permanently.