Choosing an OSR System for Hot Springs Island

My notes for making the decision

29-09-2020 - 5 minutes, 10 seconds -
osr hotspringsisland theblackhack knave mazerats fivetorchesdeep

I've been wanting to run The Dark of Hot Springs Island ever since I discovered it this spring. Even though I have the pdf I feel like a game like this deserves to be run with the hardcover books. Especially the excellent player-facing Field Guide.

I have decided to run it with an OSR system, but there are so many out there that it's not a super easy decision. I wanted something that could handle these criteria:

  • Survival mechanics
  • Limited inventory capacity
  • Low power level
  • Interesting classes
  • Fun advancement system
  • Easy to prep and run

I chose between Knave, The Black Hack, Five Torches Deep, and DCC RPG. In the end I decided to go with The Black Hack.

I like how it has so many interesting mechanics that add to the fun without feeling cumbersome or crunchy. I hope it'll be a great fit. I'll be posting some play reports once the campaign gets going in a week or two.

You can see all my (unedited) notes for making the decision below. These comments are mostly based on my perceived fit for Hot Springs Island, so even though I might have given them a low grade, they might be perfect for other adventure modules.


  • Great at low levels
  • Quick to roll new characters
  • Easy to learn (one page of rules, same attributes as D&D)
  • Compatible with OSR stats out of the box
  • Simple encumbrance system (CON # of items)
  • Magic is not well-defined and depends on GM rulings
  • Character advancement is very limited. Everything depends on gear
  • Perhaps a bit too scaled down. Easy to GM but boring for the players . No skills (use Maze Rats/DCC backgrounds)

    Comment: Good system but very barebones. Probably great for a one-shot but not for a campaign. Verdict: 2/5

The Black Hack

  • Cool out of action table instead of instant death
  • The "sharing experience" system is fun
  • Usage dice for consumables is nice
  • Simple encumbrance system (STR # of items)
  • Has tables for diseases, narcotics, and poison
  • Great rules for hirelings and retainers (they all have specializations)
  • All rules to run the game in less than 30 pages
  • Has an official GM screen
  • Has spell/prayer books to be printed
  • Armour dice system is pretty cool. Break armor pieces to ignore damage. Repair when resting
  • Compatible with OSR stats (has great table for determining damage depending on HD)
  • Has a ton of fantastic tables and random generators
  • Very different from D&D which might be confusing to some players . Character advancement is perhaps a bit too basic (but all classes get stuff that scales with levels) . Must add d4 to hit roll with two-handed weapons . Roll under mechanic (looks cool, but unusual for players) . Player-facing rolls to defend . Fairly basic magic system with few spells. Easy to keep track of, but is it fun? . Simple skill system (most skills from background/stats or class and may use background to get advantage on one roll/day) . Must find magic spells or prayers in the world (there's a table to roll for who has the spell) . Weapons are kind of bland because all classes have a basic attack damage . Can easily be expanded with more classes

    Comment: Fantastic system which has almost everything I want for Hot Springs Island. Might want to change up character advancement and add some more classes. Verdict: 4/5

Five Torches Deep

  • Easy to learn (similar to 5e)
  • Lots of nice class archetypes with distinct features
  • Meaningful choices at level up after level 3
  • Decent weapon system (nice rules for dual-wielding, roll 2d6 and take the highest d6 for damage)
  • Simple encumbrance system (STR # of "load")
  • Has a system for crafting
  • Great system for death and injury (table with different stat losses/death/etc)
  • Has rules for timekeeping
  • Magical mishap table
  • Spell lists are scaled down and pretty good (except for cantrips)
  • Can be run with 5e monsters (just 1/2 hp and convert CR to HD)
  • The power level is much higher than other OSR games (a minimum of +3 to your class rolls at the start, very strong class features, high damage, high hp)
  • Too high HP awarded at level up (1d10 + CON mod for warriors)
  • XP for gold requires way too much gold (2500 for the first level)
  • Way too powerful and many starting items
  • Few mundane items to roll for at the start ("sundries" table at the end of the book)
  • Has "quick actions" like bonus actions (yet another thing to make PCs more powerful)
  • Coins are way too light
  • Has cantrips that can be cast infinitely without risk of failure
  • The retainer rules are pretty meh
  • OSR stats cannot be run out of the box (there is a conversion guide though) . "SUP" or supply system for consumables (not super intuitive or fun, not sure it's better than counting individual items) . Odd foraging system for replenishing SUP . Crit fails can break items (DUR or "durability" points) . Monster stat blocks are decent but still fairly different from most OSR

    Comment: The system looks decent but has a bit too high power level. I like the character advancement and choices. Verdict: 3/5


  • Crits and fumbles are hilarious
  • Fantastic magic system (tables for EVERY spell)
  • Burning stats for casting spells is awesome
  • Detailed skills for each class
  • Every level up feels rewarding
  • The magic system is fantastic
  • Luck is fun (at least at level 0)
  • A bit more crunchy than the other games (but definitely lighter than D&D)
  • Weird dice
  • Class archetypes are basic and boring
  • Not compatible with OSR monster stats out of the box (just hit dice) . Race as class (dwarf, halfling, elf)

    Comment: Super fun at level 0. A bit crunchy after level 1. Odd and gonzo. Weird dice are a big no no for online games. Requires a bit more prep. Feels like more of a one-shot system. Verdict: 3/5

Things I might want to add to The Black Hack:

  • Starting items from Knave and Maze Rats
  • Occupation/background tables from DCC and Maze Rats
  • Appearance/manner tables from Knave and Maze Rats
  • Item lists from Knave
  • 0-level funnel from DCC (perhaps borrow Luck too, just for level 0)