Bug Heroes 2 features single player missions.
Horde: Defend against a huge onslaught of enemies (w/o stash) for a set number of turns, varying in power, number and type via star difficulty.
War: Defend your stash from consistent waves of enemies for a set number of turns, varying in degree and type via star difficulty.
Assassinate: (Plays as a normal Endless game) Defend your stash until a specified very powerful bug(s) appear, then take it(them) down to complete the mission. (varying via star difficulty).
Architect: Survive a certain amount of rounds with a certain tower type(s) of a certain level (eg. "We've got to fortify the Food Stash! Complete 2 rounds with 1 level 1 Slime Quarters turret!"), varying via star difficulty.
Defend: Defend your stash against a certain type of enemy bug for a set number of rounds, varying via star difficulty.
Survive: Survive for a certain amount of minutes without food stash and spare part upgrade is doubled, varying via star difficulty.
Each mission will reward, upon completion, diamonds and upgrade stars. The reward depends on the difficulty of the mission, as well as any potential bonuses the player may receive if they fulfill the requirement (ie. Using specific characters). These reward bonuses come in the form of additional stars or additional diamonds per "bonus bug" used. Losing a mission (losing, not quitting) twice reduces its difficulty, but slightly lowers the star amd diamond reward.