The objective of Lowlife is to heal your party and keep them alive while they fight Villains on their own. When you enter a Simulation, Lab, or Raid, your Scripts (Party Members) will automatically cycle through their Executables, which are the RPG equivalent of skills or spells. They will take damage from the Villain you are currently fighting while also dishing it out.
The amount of damage they give and receive to and from Villains are dictated by the Power Level (Lv.) discrepency between the Villain and Script, amongst other unique stats and Buffs. When you notice their health dropping, tap on them to select them. The selected Script will have a green circle with an arrow to indicate they are selected. To heal them, tap on one of your Healing Executables (RPG equivalent of Spells) toward the bottom of your screen. You will begin Lowlife with just Quick Heal unlocked and as you level up by defeating Villains you will unlock all 10 of your Healing Executables. As you unlock more Healing Executables, managing your Mana and picking the right Heal to use at a given time will become much more important.
You will randomly find new, stronger Scripts as you defeat Villains or complete Quests, and they can be set up in the Scripts screen (see next section for details). They can also be found in the Markets screen for sale by an in-game Vendor or even by other Lowlife players worldwide in the Auction House. Scripts have different rarities which dictate how many Executables (Skills and Spells) they can randomly roll with. They will also have bonuses to your Parameters, which are like your attributes and give you passive buffs to your casting speed, mana regeneration, healing power, and more. More details about Parameters are explained in the Parameters screen of the game. Scripts also have their own attributes: Speed (SPD), Defense (DEF), and Attack (ATK). These are modifiers which slightly affect how fast they can cast an Executable, bonuses to resisting damage, and bonuses to doing damage, respectively.
The main gameplay takes place in the Simulations, which are like Dungeons with different sets of Villains. Each Simulation has 9 Versions with increasing difficulty. When you defeat the Boss in any Simulation Version, the next Version will unlock. Different Simulations are unlocked via you reaching a certain Player Level, and others are unlocked with random drops from defeating Boss Villains (i.e. they will drop some sort of key).
As you defeat Villains, you and your Scripts will gain XP to Level up. The Level of yourself and Scripts will affect how much base damage you do to Villains and how much they do to you. Ideally you want to have your Scripts and self the same Level as the Villains you face so you deal good damage and take less damage. For those who like a challenge, it is not impossible to take on Villains higher Level than you! When defeating a Villain, the Player will receive full XP from the encounter, and another pool of XP will be divided amongst the equipped Scripts based on how much damage they dealt in the fight. For Scripts that might be lagging behind in XP gains, they can be manually Leveled Up in the Scripts screen with Memories, the currency you gain from deleting Villains.