Riryoku is a very powerful card and ranks highly in terms of card efficiency due to its ability to both decrease your opponent’s monster ATK and add it to your own. Unlike equip cards, Riryoku could only be negated by spell jammer or counter traps which could negate spell effects. Could be included in most decks that otherwise do not use effect damage to win.
Very useful to defeat any high level attack monster.
Damage dealt is similar to direct damage, since it is the base attack of the attacking monster.
Very flexible card.
Only useful for 1 turn.
This cards effect only lasts for a turn, so use it wisely. It's usually best to use it on targets that have higher ATK than anything you have on the board or in your hand.
Riryoku works well in any beatdown deck and is necessary to decks to get high score with Over 5,000 (9,999) Damage duel assessment. → How to get high score
Not sure why this card is rated as a 9.5. You should only ever run this card in farming decks to increase Cerberus's attack, and never in PVP. Cards like Metalmorph or even other continuous spells such as Gravity Axe are more useful since they are permanent buffs and can't be negated as easily as Riryoku. Nearly every deck has Windstorm of Etaqua, and 1 or more copies of both Enemy Controller and Sphere Kuriboh, which basically just makes Riryoku a wasted card
If your deck has space left to add something, add something far more useful than a fucking Riryoku. A tech like Wild Tornado, a single tribute monster (like Knight of the Red Lotus in Harpies), or literally anything else. The guy that said he reached KoG with Riryoku hasn't even demonstrated it!
Do you know that "Riryoku" means "Force/Strength" in Japanese?
Well, guess what this card is called in Japan? It is just called "Force"(フォース). Oh, and Riryoku Field is just called Force Field in Japan. Somehow the translator thinks that calling this card "Riryoku" is more straight-forward than calling it "Force".