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

Optimization · Pure Optimization
The beloved DS remake of Johto with walking companions and both Johto and Kanto to conquer.

Optimization · Pure Optimization
Deep empire optimisation over a hidden map against mappable AI.
Pokemon HeartGold Version leans Optimization (Pure Optimization); Sid Meier's Civilization IV 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.
Pokemon HeartGold Version
Menu battles; no physical skill tested
Sid Meier's Civilization IV
Turn-based clicks have no physical ceiling
Same score on reads - which means the number cannot separate them. The difference is in what each one asks of you.
Pokemon HeartGold Version
Scripted trainer AI; online battles optional
Sid Meier's Civilization IV
Human multiplayer adds diplomacy reads; AI is mappable
Sid Meier's Civilization IV leans a little harder on variance, though the gap is small.
Pokemon HeartGold Version
Encounter RNG, catch rates, Pokewalker luck
Sid Meier's Civilization IV
Map generation and unrevealed terrain drive early decisions
Sid Meier's Civilization IV leans a little harder on optimization, though the gap is small.
Pokemon HeartGold Version
Sixteen badges of team building and matchup planning
Sid Meier's Civilization IV
Tech paths, tile yields and expansion math dominate outcomes
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.