head to head
Neither is simply harder - they are hard in different places. Thief Town demands more reads; Worms W.M.D demands more optimization.

Reads · Pure Mind Games
A local-multiplayer stealth game about blending in and reading which figures are human.

Reads · Competitive PvP
Modern Worms with crafting and vehicles, keeping the classic turn-based destructible-terrain warfare.
Thief Town leans Reads (Pure Mind Games); Worms W.M.D leans Reads (Competitive PvP).
Worms W.M.D leans a little harder on execution, though the gap is small.
Thief Town
Timed stab inputs matter but aren't the ceiling
Worms W.M.D
Shot arcs, rope swings and vehicle control demand precision
Thief Town leans clearly harder on reads.
Thief Town
Reading human players hiding among NPCs is the core
Worms W.M.D
Multiplayer turns hinge on out-guessing rival worm placement
Worms W.M.D leans a little harder on variance, though the gap is small.
Thief Town
Crowd of identical NPCs hides players, adding uncertainty
Worms W.M.D
Wind, crates and random terrain reshape options
Worms W.M.D leans clearly harder on optimization.
Thief Town
Little system to solve beyond the bluffing layer
Worms W.M.D
Crafting and weapon budgeting reward planned turns
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.