Missions
Missions will earn you XP, cash, free science points, and occasionally, an add-on bonus to upgrade a henchmen. When you reach 100% mastery for a mission, you receive one free science point. Each mission has 3 tiers of mastery, giving you a potential of 3 free science points for every mission available.
The most common mistake among inexperienced players is that they get caught in a mission leveling cycle, meaning that they depend on missions for their income and XP. When you rely on missions to build your income, you can become a very weak player very quickly, and at higher levels, players will be able to defeat you very easily.
Each mission will require a set amount of energy, and 98% of the time, you will also need certain henchmen and vehicles.
Every mission has a success rate, if the success rate is not shown, then you have achieved a high enough level for a 100% success rate. Keep in mind that the success rate on these missions are not additive, meaning that if a mission has a success rate of 5% you might have to attempt it more than 20 times to successfully complete it.
As you level up, you might be tempted to put some of your attribute points into energy. If you want to be a strong villain, then you should not put any points into energy; instead, you should put your attribute points into attack, defense or HP. Some missions will require more than the 10 energy you start off with; this is where energy drinks come in handy. You can use an energy drink or stamina bar once every 18 hours, and the amount of energy or stamina you can stack is indefinite, you can potentially have 9999/10 energy or 9999/4 stamina.
To unlock the next set of missions, you must complete the boss mission.
Boss Missions
Boss missions will potentially allow you to unlock henchmen and vehicles earlier than normal.
Many players will attempt to complete boss missions even when they only have a 5% success rate in order to unlock henchmen and vehicles as early as possible.
Every time you level up, a mission's success rate will increase by 7.5% to a maximum of 100%. If a mission set was unlocked at level 20, then by level 30 you would have a 75% success rate, and if you completed that boss mission then the next boss mission would have a 5% success rate.
From levels 1-19, there will be a new set of missions every 5 levels, but after level 20, a new set of boss missions will only be available every 10 levels.