Arrhenius
Core RulebookCore Mechanic
For skill checks, roll a d20 and add the two relevant Talents plus the applicable Education score. A total of 21 or higher succeeds. Before a non-damage d20 roll, Luck Points can add +1 each to its bonus.
Best For
Groups who want a survival-focused science-fiction campaign where characters cross frozen ruins, manage limited equipment, and resolve fights on a tactical grid.
Highlights
Frost Points turn prolonged exposure to subzero conditions into resilience checks, so shelter and protective gear shape expeditions. The optional Tuning Session assigns Talent scores through a short character-memory scenario, tying early choices to the resulting build. Combat uses a 2-meter grid with optional Perks that award attack bonuses for flanking or high ground.
Considerations
Skill bonuses combine two Talents with an Education score, so ordinary checks require a layered character sheet. A natural 1 can give a Strike to gear used in the failed skill check, so critical failures can damage equipment. Combat follows a step-by-step flow from initiative through opposed rolls and special procedures, so fights carry more steps than a rules-light game.