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.

Optimization · Pure Optimization
Alternate-history RTS where economy management and build orders win wars.

Optimization · Practiced Mastery
A free-to-play shooter where you build custom fighting vehicles from blocks and battle other players' creations.
Command & Conquer: Red Alert leans Optimization (Pure Optimization); Robocraft leans Optimization (Practiced Mastery).
Same score on execution - which means the number cannot separate them. The difference is in what each one asks of you.
Command & Conquer: Red Alert
Micro and base management under time pressure
Robocraft
Aiming and piloting matter but vehicles are sluggish
Same score on reads - which means the number cannot separate them. The difference is in what each one asks of you.
Command & Conquer: Red Alert
PvP skirmish rewards predicting enemy pushes
Robocraft
Human PvP battles reward outflanking live opponents
Command & Conquer: Red Alert leans a little harder on variance, though the gap is small.
Command & Conquer: Red Alert
Fog of war conceals army composition
Robocraft
Matchmaking and map spawns add mild noise
Command & Conquer: Red Alert leans a little harder on optimization, though the gap is small.
Command & Conquer: Red Alert
Ore economy and build orders decide games
Robocraft
Block-by-block build crafting and meta loadouts dominate outcomes
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.