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

Execution · Pure Mechanics
An explosively destructible run-and-gun starring parody action-movie heroes.

Execution · Pure Mechanics
Raw arcade reflexes against accelerating swarms with mild spawn randomness.
Broforce leans Execution (Pure Mechanics); Millipede leans Execution (Pure Mechanics).
Millipede leans a little harder on execution, though the gap is small.
Broforce
Run-and-gun reflexes amid constant explosions
Millipede
Trackball precision under swarming pressure is everything
Same score on reads - which means the number cannot separate them. The difference is in what each one asks of you.
Broforce
Enemies are dumb scripts
Millipede
Enemies follow fixed movement rules
Same score on variance - which means the number cannot separate them. The difference is in what each one asks of you.
Broforce
Random bro assignments and destructible chaos shake runs
Millipede
Spawn waves and DDT timing vary run to run
Broforce leans a little harder on optimization, though the gap is small.
Broforce
Knowing each bro's kit and level layouts helps
Millipede
Mushroom-field management is a thin strategic layer
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.