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

Execution · Pure Mechanics
A rally racer where mastering precise car control against tricky terrain is everything.

Execution · Pure Mechanics
Classic Tetris execution under audiovisual flow, speed still decides everything.
Colin McRae: Dirt 2 leans Execution (Pure Mechanics); Tetris Effect leans Execution (Pure Mechanics).
Same score on execution - which means the number cannot separate them. The difference is in what each one asks of you.
Colin McRae: Dirt 2
precise rally driving and braking required
Tetris Effect
Piece placement under speed and Zone timing is the whole test
Same score on reads - which means the number cannot separate them. The difference is in what each one asks of you.
Colin McRae: Dirt 2
no adaptive opponents, mostly time trials
Tetris Effect
Solo experience with no opponent to model
Same score on variance - which means the number cannot separate them. The difference is in what each one asks of you.
Colin McRae: Dirt 2
weather and surface conditions vary
Tetris Effect
Randomised bag is bounded and quickly mappable
Same score on optimization - which means the number cannot separate them. The difference is in what each one asks of you.
Colin McRae: Dirt 2
car tuning and racing lines solvable
Tetris Effect
Stacking theory and Zone usage have known optimal lines
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.