head to head
Left 4 Dead asks more than Coffin Dodgers, and the gap is optimization.

Execution · Twitch Chaos
A kart racer about battling the Grim Reaper on weaponized mobility scooters.

Execution · Twitch Chaos
Co-op zombie shooter whose AI Director reshuffles every run to keep teams honest.
Coffin Dodgers leans Execution (Twitch Chaos); Left 4 Dead leans Execution (Twitch Chaos).
Left 4 Dead leans a little harder on execution, though the gap is small.
Coffin Dodgers
Steering scooters and aiming weapons tests reflexes
Left 4 Dead
Headshots, melee shoves, and special-infected reaction time
Same score on reads - which means the number cannot separate them. The difference is in what each one asks of you.
Coffin Dodgers
AI racers scripted; human opponents somewhat anticipatable
Left 4 Dead
Versus mode adds human ambush mindgames
Left 4 Dead leans a little harder on variance, though the gap is small.
Coffin Dodgers
Weapon pickups and item drops add kart-racer randomness
Left 4 Dead
AI Director randomizes hordes, items, and specials
Left 4 Dead leans clearly harder on optimization.
Coffin Dodgers
Item usage and racing lines are light strategy
Left 4 Dead
Team spacing, route choice, and resource discipline
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.