So from the get go you are not really taught the controls for the games. All of them use the z and x key, with Z being the main attack and main menu selector and x being the secondary attack.
For tower of succubus the objective is to get to the top of the tower but in various rooms there are notebooks that give the locations of treasure such as heart pieces to increase health.
Below your character on the right side you will notice 2 things (okay, maybe 3 since your lewd char is RIGHT there in all her glory) the first being a magic pic with a number and a heart pic with a number.
Your magic damage increases as you level up and your heart number increases when you pick up little hearts and “defeat” enemies.
Enemies “defeated” give about 10 heart power. What is this used for? Well when holding z and x together you can activate your special, this refils your health and magic fully at the cost of 50 heart power, very useful for bosses but be wary as you can only use a special one time each time you enter a floor.