What’s the simplest way to add a level unlocking system?
For example, when “X objective value is met” in level 1, Unlock level 2.
Any help with this would be appreciated! Thanks! 
One simple way of doing this might simply be to create a SaveGame Object specifically for level unlocks which could contain variables for each unlock or even a custom struct or an array. Basically just containing a bunch of boolean variables.
In the previous level you could have the level blueprint change the next level’s unlock in the savegame object to be True rather than False.
And when moving between levels, you would only have to reference the savegame object and check each level against the unlock list