So Archquest is single player, and the player is trying to advance through multiple quests to finally get to a military compound and steal a crystal from being destroyed, for it is last hope.
Now some instructions:
For villains, you could add guards to prevent the player from retrieving the crystal.
You could add gates. Like Gate 1, Gate ", e.t.c.
And at each gate, you could add a specific boss for the player to fight.
About the lore, maybe the villains are destroying the crystal because its the only way to stop them from destroying the planet or something.
The crystal could have been used to power up a powerful cannon that can defeat the villains which is why they want to get rid of it.
For the quest ideas, you can collect map pieces or parts that could more enhance your gadgets.
Maybe help other people who have been affected by the stolen crystal.
Hmm…
Maybe, the Crystal posesses some kind of cosmic power, and the villains want to harness that power? Idk man-
These some good ideas. I will definitely use some of these…