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

Optimization · Pure Optimization
A maze-building tower defense about optimizing tower placement against scripted enemy waves.

Optimization · Pure Optimization
A castle-building strategy game where economic optimization and defense planning is the whole test.
Fieldrunners 2 leans Optimization (Pure Optimization); Stronghold 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.
Fieldrunners 2
Placing towers - no twitch dimension
Stronghold
minimal, mostly clicking and management
Stronghold leans a little harder on reads, though the gap is small.
Fieldrunners 2
Enemies follow fixed paths, not adaptation
Stronghold
AI opponents are scripted, minor prediction
Same score on variance - which means the number cannot separate them. The difference is in what each one asks of you.
Fieldrunners 2
Wave composition scripted-but-unknown first time
Stronghold
minor resource and raid randomness
Same score on optimization - which means the number cannot separate them. The difference is in what each one asks of you.
Fieldrunners 2
Maze layouts and tower mixes are the solvable puzzle
Stronghold
economy and castle-building near-solvable
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.