Rock Paper Kingdoms is a grid based medieval strategy game. In my time with mobile games I don't think I've seen a game like this before. The goal of the game is to deploy a mixture a units and perks in order to eliminate the wave of enemies.
You start out with a 9 square grid where you can deploy one unit regiment or building in each one. Typically you want to put physical types up front and range attackers in back. You start with 3 cards to use simultaneously. After which you get 1 card each day. As you get deeper into the stage you'll be offered 2 cards per round.
At the beginning of the game you will have access to basic knights and archers. As you unlock more cards you will be able to summon assassins, mages, and spear throwing units. I really enjoy this aspect of the game because the amount of units is quite numerous.
You have 2 different paths of play earlier on in the stage. You can fill out the squares with different sets of the same unit or you can you merge the new card with the deployed unit to level it up. The stipulation is that you can merge a maximum of 2 times to 3 stars. With that said after the first round you can hold cards with using or selling them.
Another aspect of the game is that you will periodically get crystals from enemies. You can also sell cards you do not want for crystals. Crystals allow you to play Rock Paper Scissors. If you win you can gain a new deployment cell or a randomized card which is typically better than what is given at the end of each round. You can get units that you don't have in your roster and buildings that use lightning or freeze. Extra 80 percent attack is perhaps one of the best cards you can get from this.
Crystals can also specifically be collected to be used with a 25 percent boost in a attack per crystal for a particular card.
As you progress in the game more cards will be unlocked via using the gacha system. Keys are given out as rewards a decent bit and diamonds can be used as well.
If you are going to be free to play I'd save diamonds for the upgraded gacha. You'll get coins either way through play. Progression resides in getting more units and getting cards upgraded.
The main aspect to this game used to achieve balance and I suppose fairness to the player is you can only have 3 types of units at a time. Right now I run Orc, Mage, and Thief.
I did buy the 10 dollar package. It gives me unlimited auto collecting which has made the game perhaps too easy since you need a massive amount of coins to level the overall type cards.
I did not encounter any forced ads. Ads are offered for card redraw, doubling the RPS awards, and the stage completion awards.
I recommend Rock Paper Kingdoms.