These are what we call the 'YMMV items.' Things that some people find in this work. We call them 'your mileage might vary' because not everyone sees these things in the same way. This starts discussions in the trope lists, a thing we don't want. Please use the discussion page if you'd like to discuss any of these items.
In Armies of Gielinor, it used to be possible to block the opponent's portal by parking a flying unit on top of it—potentially locking them out of summoning units for the rest of the game if they lacked a ranged unit to attack it. Portals have since been updated to deal damage to enemy units that camp on top of them.
Those with a decent knowledge of mathematical theory may realize Tetralink, like any connect-4 variant, is mathematically solvable and you can guarantee yourself a 100% win rate with the appropriate guides.