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.

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

Execution · Pure Mechanics
An endless runner testing reactive jump and dash timing for distance.
Colin McRae: Dirt 2 leans Execution (Pure Mechanics); Robot Unicorn Attack 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
Robot Unicorn Attack
Precise jump and dash timing decides every run
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
Robot Unicorn Attack
Solo endless runner, no opponent
Robot Unicorn Attack leans a little harder on variance, though the gap is small.
Colin McRae: Dirt 2
weather and surface conditions vary
Robot Unicorn Attack
Procedural obstacle generation adds reaction demand
Colin McRae: Dirt 2 leans a little harder on optimization, though the gap is small.
Colin McRae: Dirt 2
car tuning and racing lines solvable
Robot Unicorn Attack
Limited strategy beyond reactive timing
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.