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 · Pure Optimization
A post-nuclear RPG expanded in scope where tagged builds and Gifted-trait optimization dominate.

Optimization · Pure Optimization
A merge-puzzle auto-battler about composing strong squads to retake castles.
Fallout 2 leans Optimization (Pure Optimization); Merge & Blade leans Optimization (Pure Optimization).
Same score on execution - which means the number cannot separate them. The difference is in what each one asks of you.
Fallout 2
Turn-based AP system makes twitch entirely irrelevant
Merge & Blade
Placing and merging units, no twitch input
Same score on reads - which means the number cannot separate them. The difference is in what each one asks of you.
Fallout 2
All tribal and Enclave enemies run fixed scripted combat routines
Merge & Blade
Monster armies scripted, not adaptive opponents
Same score on variance - which means the number cannot separate them. The difference is in what each one asks of you.
Fallout 2
Hidden special encounters and timed events create significant unknown-information space
Merge & Blade
Unit draws from merging inject roguelike randomness
Fallout 2 leans a little harder on optimization, though the gap is small.
Fallout 2
SPECIAL and skill tagging with Gifted trait produce well-known dominant build strategies
Merge & Blade
Building optimal merged squads for auto-battles is the game
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.