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

Execution · Pure Mechanics
Keeping speed through destruction-racing chaos that punishes clean-lap plans.

Execution · Pure Mechanics
Twitch top-down driving and weapon chaos against friends on a couch.
FlatOut: Ultimate Carnage leans Execution (Pure Mechanics); Mashed: Drive to Survive 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.
FlatOut: Ultimate Carnage
Holding racing lines through wrecks and ragdoll chaos tests hands
Mashed: Drive to Survive
Top-down cornering at speed while aiming weapons is twitchy
Mashed: Drive to Survive leans a little harder on reads, though the gap is small.
FlatOut: Ultimate Carnage
Rival drivers ram predictably, light multiplayer jockeying
Mashed: Drive to Survive
Couch rivals bait blocks and time weapon strikes
Same score on variance - which means the number cannot separate them. The difference is in what each one asks of you.
FlatOut: Ultimate Carnage
Debris and pileups scramble any planned lap
Mashed: Drive to Survive
Weapon pickups and missile strikes add party chaos
FlatOut: Ultimate Carnage leans a little harder on optimization, though the gap is small.
FlatOut: Ultimate Carnage
Car upgrades and track shortcuts are mappable
Mashed: Drive to Survive
Track knowledge helps but stays shallow by design
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.