Guards

Guards are one of the main factors of the game. They normally tend to detect you when in line of sight, and if detected for long enough, they will raise an alarm, (Bob the Robber 1& 2 ) or cause bob to go busted ( Bob the Robber 3, 4, and 5 ).

Normal guards
These typical guards are seemingly very easy to knock out from the back. However, if Bob reacts quickly with the guard looking at them, he can still knock them out or move on without being fully detected.

Armored guards
These guards are normally impossible to knock out and will cause an alarm when trying to knock out them from whenever the back or front.