head to head
Neither is harder. They score identically on all four axes, so the difference between them is in kind, not degree.

Execution · Practiced Mastery
Crude comedy 3D platformer of boss fights, parodies, and set-piece variety.

Execution · Practiced Mastery
Dark-fantasy Doom-engine shooter trading shotguns for elven wands and tomes.
Conker's Bad Fur Day leans Execution (Practiced Mastery); Heretic leans Execution (Practiced Mastery).
Same score on execution - which means the number cannot separate them. The difference is in what each one asks of you.
Conker's Bad Fur Day
Varied platforming and shooting set pieces
Heretic
Classic FPS strafing and aim
Same score on reads - which means the number cannot separate them. The difference is in what each one asks of you.
Conker's Bad Fur Day
Bosses and enemies fully scripted
Heretic
Monsters follow fixed 90s AI
Same score on variance - which means the number cannot separate them. The difference is in what each one asks of you.
Conker's Bad Fur Day
Linear, authored content throughout
Heretic
Static level layouts
Same score on optimization - which means the number cannot separate them. The difference is in what each one asks of you.
Conker's Bad Fur Day
Context-sensitive solutions are learnable
Heretic
Secret hunting, item hoarding, and route knowledge
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.