head to head
Ghosts 'n Goblins asks more than Half-Life 2, and the gap is execution.

Execution · Pure Mechanics
Capcom's infamously punishing arcade platformer that makes you beat it twice for the real ending.

Execution · Pure Mechanics
Landmark FPS built on physics puzzles and tight gunplay.
Ghosts 'n Goblins leans Execution (Pure Mechanics); Half-Life 2 leans Execution (Pure Mechanics).
Ghosts 'n Goblins leans clearly harder on execution.
Ghosts 'n Goblins
Committed jumps and pixel-precise throws, no mercy
Half-Life 2
Gravity gun and shooting demand precision.
Half-Life 2 leans a little harder on reads, though the gap is small.
Ghosts 'n Goblins
Enemy spawns are scripted
Half-Life 2
Combine AI scripted, non-adaptive.
Same score on variance - which means the number cannot separate them. The difference is in what each one asks of you.
Ghosts 'n Goblins
Red Arremer movement adds slight noise
Half-Life 2
Almost no randomness.
Ghosts 'n Goblins leans clearly harder on optimization.
Ghosts 'n Goblins
Weapon choice and route memorisation are mandatory
Half-Life 2
Linear progression with no builds.
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.