head to head
Neither is simply harder - they are hard in different places. Hearthstone demands more optimization; Town of Salem 2 demands more reads.

Variance · Grand Arena
A digital card game balancing opponent reads against draw variance.

Reads · Bluff & Deduction
A town full of hidden roles lies, deduces, and lynches its way to a faction victory.
Hearthstone leans Variance (Grand Arena); Town of Salem 2 leans Reads (Bluff & Deduction).
Hearthstone leans a little harder on execution, though the gap is small.
Hearthstone
Clicks only, no mechanical skill
Town of Salem 2
Text chat and votes; no mechanical skill at all.
Town of Salem 2 leans clearly harder on reads.
Hearthstone
Human opponents bluff and adapt mid-match
Town of Salem 2
Out-bluffing adaptive humans who model your claims is the game.
Same score on variance - which means the number cannot separate them. The difference is in what each one asks of you.
Hearthstone
Draw RNG and discover effects swing games
Town of Salem 2
Hidden roles and random role lists dominate early information.
Hearthstone leans clearly harder on optimization.
Hearthstone
Deckbuilding, mulligans, and mana curves matter
Town of Salem 2
Role mechanics, claim space, and voting math reward study.
A matching score does not mean a matching test. Two games can both sit at 10 on execution and demand completely different things of you - which is why the reasoning above matters more than the number beside it.