When braking the car doesn't stop as quickly as it did before, it needs more force applied to the brake pedal.
The brake pedal takes a lot of effort to press down to the level needed to slow the car down effectively. It's much harder to press the pedal in than it normally is.
When pressing the brake pedal the brakes don't apply in a smooth way, they seem to come on all of a sudden and are more bumpy than they used to be.