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
Budgeting steam movement and loadouts against hidden but scripted alien positions.

Optimization · Pure Optimization
Villainous dungeon management game about luring monsters and crushing do-gooder heroes.
Code Name S.T.E.A.M. leans Optimization (Pure Optimization); Dungeon Keeper 2 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.
Code Name S.T.E.A.M.
Manual third-person aiming adds a real but small hands layer
Dungeon Keeper 2
Slap-and-drop micro and possession combat need quick hands.
Same score on reads - which means the number cannot separate them. The difference is in what each one asks of you.
Code Name S.T.E.A.M.
Alien AI runs fixed behaviours, never modelling you
Dungeon Keeper 2
Hero waves and rival keepers run on scripts.
Code Name S.T.E.A.M. leans a little harder on variance, though the gap is small.
Code Name S.T.E.A.M.
Unseen enemy positions and overwatch threats are hidden information
Dungeon Keeper 2
Hero party timing and creature moods vary mildly.
Same score on optimization - which means the number cannot separate them. The difference is in what each one asks of you.
Code Name S.T.E.A.M.
Steam budgeting, loadouts and positioning are the solvable core
Dungeon Keeper 2
Dungeon layout, creature economy and research are 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.