There are so many little tips and tricks that could make a player's first experiences in XCOM 2 more positive, but the game just doesn't communicate many of the most crucial details. Case and point: Flashbangs counter Sectoids incredibly effectively, disrupting their psionic holds and preventing them from using the same move in the next turn. Considering just how frustrating, and potentially devastating the mind control ability can be to an underprepared team, this is a vital little trick that everything needs to be aware of. It allows you to deal with Sectoids without forcing you to move position, which can make or break a given situation.