The second tier of Looking Cross requires you to perform variable counters, infinity counters, or infinity gem counters 25 times. Counters are done while you're blocking an attack. Wait for your opponent to attack you, and when you see the animation of your character blocking, input the command for a counter. You'll interrupt their attack and counter with your own move.
Variable Counter: ++ while blocking in Marvel vs Capcom. Costs 1 hyper meter.
Infinity Counter: + while blocking in Marvel Super Heroes. Costs 1 hyper meter.
Gem Counter: + near an attacking opponent in Marvel Super Heroes. Costs 1 gem.