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

Reads · Bluff & Deduction
Spacemen complete station tasks while a shapeshifting monster impersonates and eats them.

Reads · Competitive PvP
Modern Worms with crafting and vehicles, keeping the classic turn-based destructible-terrain warfare.
Unfortunate Spacemen leans Reads (Bluff & Deduction); Worms W.M.D leans Reads (Competitive PvP).
Worms W.M.D leans a little harder on execution, though the gap is small.
Unfortunate Spacemen
Shooter combat matters once the monster is exposed.
Worms W.M.D
Shot arcs, rope swings and vehicle control demand precision
Unfortunate Spacemen leans clearly harder on reads.
Unfortunate Spacemen
The shapeshifter wins by out-modeling suspicious human crewmates.
Worms W.M.D
Multiplayer turns hinge on out-guessing rival worm placement
Unfortunate Spacemen leans clearly harder on variance.
Unfortunate Spacemen
Hidden monster identity and random objectives drive uncertainty.
Worms W.M.D
Wind, crates and random terrain reshape options
Worms W.M.D leans clearly harder on optimization.
Unfortunate Spacemen
Station layouts and objective flow reward repetition modestly.
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.