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
Twitch tank duels while protecting a base from scripted enemy waves.

Execution · Pure Mechanics
Tetris with a puzzle mode - still a test of placement speed and stacking craft.
Battle City leans Execution (Pure Mechanics); Tetris Plus leans Execution (Pure Mechanics).
Tetris Plus leans a little harder on execution, though the gap is small.
Battle City
Tank aim and dodge timing under pressure decides every stage
Tetris Plus
Piece placement speed under pressure decides everything
Tetris Plus leans a little harder on reads, though the gap is small.
Battle City
Enemy tanks follow simple scripted routines, nothing adaptive
Tetris Plus
Versus mode adds only light opponent awareness
Same score on variance - which means the number cannot separate them. The difference is in what each one asks of you.
Battle City
Spawn order and power-ups add mild randomness per stage
Tetris Plus
Random piece order is bounded and rapidly mappable
Same score on optimization - which means the number cannot separate them. The difference is in what each one asks of you.
Battle City
Base-defense positioning and brick management have known best answers
Tetris Plus
Puzzle-mode professor routes have known optimal solutions
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.