head to head
Celeste asks more than Half-Life 2, and the gap is execution.

Execution · Pure Mechanics
A deterministic precision platformer about executing pixel-perfect dash routes.

Execution · Pure Mechanics
Landmark FPS built on physics puzzles and tight gunplay.
Celeste leans Execution (Pure Mechanics); Half-Life 2 leans Execution (Pure Mechanics).
Celeste leans clearly harder on execution.
Celeste
Pixel-perfect dashes and wavedashes are the entire skill.
Half-Life 2
Gravity gun and shooting demand precision.
Half-Life 2 leans a little harder on reads, though the gap is small.
Celeste
No opponent; level hazards are fully scripted.
Half-Life 2
Combine AI scripted, non-adaptive.
Half-Life 2 leans a little harder on variance, though the gap is small.
Celeste
Zero randomness; every screen is deterministic.
Half-Life 2
Almost no randomness.
Celeste leans a little harder on optimization, though the gap is small.
Celeste
Route choice and tech selection are learnable but light.
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.