head to head
Neither is meaningfully harder - they pose close to the same test. The widest gap is optimization, and it is a single point.

Execution · Pure Mechanics
Cave's hardest bullet hell, built on suicidal close-range scoring and merciless execution demands.

Execution · Pure Mechanics
A pure time-attack arcade racer testing flawless car control on precision platform tracks.
Ketsui: Kizuna Jigoku Tachi leans Execution (Pure Mechanics); Trackmania Turbo 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.
Ketsui: Kizuna Jigoku Tachi
Point-blank chip harvesting in bullet storms, brutal physical ceiling
Trackmania Turbo
Platform-racer precision; every millisecond of input matters
Same score on reads - which means the number cannot separate them. The difference is in what each one asks of you.
Ketsui: Kizuna Jigoku Tachi
Enemies follow fixed scripts
Trackmania Turbo
Ghost-only competition; no adaptive opponent
Same score on variance - which means the number cannot separate them. The difference is in what each one asks of you.
Ketsui: Kizuna Jigoku Tachi
Deterministic patterns, trivial randomness
Trackmania Turbo
Deterministic tracks with no hidden randomness
Ketsui: Kizuna Jigoku Tachi leans a little harder on optimization, though the gap is small.
Ketsui: Kizuna Jigoku Tachi
Multiplier chip routing is a solved-route discipline
Trackmania Turbo
Finding the fastest line and technique per track is fully solvable
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.