head to head
Neither is meaningfully harder - they pose close to the same test. The widest gap is optimization, and it is a single point.

Optimization · Systems & Chaos
Baiting a rule-driven hero with tiles while playing the odds of card draws.

Optimization · Systems & Chaos
Seminal 1994 strategy game mixing global base management with brutal turn-based alien squad combat.
Guild of Dungeoneering leans Optimization (Systems & Chaos); X-COM: UFO Defense leans Optimization (Systems & Chaos).
Same score on execution - which means the number cannot separate them. The difference is in what each one asks of you.
Guild of Dungeoneering
Laying tiles and playing cards - zero twitch
X-COM: UFO Defense
Turn-based; only inventory clicking
Same score on reads - which means the number cannot separate them. The difference is in what each one asks of you.
Guild of Dungeoneering
Hero AI follows fixed lure rules, never adapts
X-COM: UFO Defense
Alien AI is scripted, never adaptive
Same score on variance - which means the number cannot separate them. The difference is in what each one asks of you.
Guild of Dungeoneering
Card draws and loot rolls swing every delve
X-COM: UFO Defense
Hit rolls, random maps, and unseen aliens punish constantly
X-COM: UFO Defense leans a little harder on optimization, though the gap is small.
Guild of Dungeoneering
Deck knowledge and dungeon-tile baiting are the solvable core
X-COM: UFO Defense
Base economy, research order, and tactical doctrine are masterable
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.