Building comparison
head to head
Defense Grid 2vsPortal
Portal asks more than Defense Grid 2, and the gap is execution.
Defense Grid 2
Optimization · Pure Optimization
A classic maze-building tower defense won almost entirely through optimal layouts.
Portal
Optimization · Pure Optimization
The portal-gun puzzle game whose solutions are everything.
Defense Grid 2 leans Optimization (Pure Optimization); Portal leans Optimization (Pure Optimization).
Defense Grid 2Portal
Axis by axis
Execution2 vs 4
Portal leans clearly harder on execution.
Defense Grid 2
Occasional orbital-ability timing, otherwise hands-off
Portal
Portal placement timing modest.
Reads0 vs 0
Same score on reads - which means the number cannot separate them. The difference is in what each one asks of you.
Defense Grid 2
Fixed alien wave scripts, nothing adapts
Portal
No adversary modeling player.
Variance1 vs 0
Defense Grid 2 leans a little harder on variance, though the gap is small.
Defense Grid 2
Spawn schedules are deterministic and previewable
Portal
Deterministic chambers; no randomness.
Optimization9 vs 8
Defense Grid 2 leans a little harder on optimization, though the gap is small.
Defense Grid 2
Maze routing and tower economy are a solvable puzzle
Portal
Pure puzzle-solving optimization.
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.