I can't create something like 'Enemy collides with Sword > Subtract 10 HP', since all the enemies in the family will lose 10 HP, unless I'm doing it wrong.
You must be doing it wrong. Families obey ordinary object picking rules. In that event, only the objects that meet the event will be affected.
[quote:18ri3ogn]Also doing something like 'Always > Enemy: Add LOS obstacle 'Barrier' seems to crash the program
Crashes are always bugs, please submit them to the tracker so we can make Construct more stable!!
See the attached file. It's a quick example proving events involving families work only on the right instances. It's also got a quick and dirty health bar implementation. The health bars are not in a container with the objects, they just 'naturally' pair up one to an instance if there's the same number of objects of each. This works with ordinary types as well and can be very useful. Hopefully it will help you see the real use of families. They can save a LOT of repeated events. I don't know how I'd manage without them!