Could someone give me the low down on these (and any other) 3rd Edition terms relating to weapons?

Keen - doubles the critical hit range on a weapon - cumulative with improved critical

Mighty - I think does extra strength damage, not sure though.

Are there others?

Umm...

Vorpal - Chance of killing things, instantly
Vampiric Regeneration - Basically health drain
Massive Criticals - Does (die roll) extra damage on criticals, above and beyond what it does normally.

Can't think of anything else right now. ;)

They all just good things to have :)

Thanks!

If you remember any others, please post them. ;)

It is for missile weapon that doesn't normally confer STR bonus tp damage - Mighty X means you get up to +X to damage (if you STR is high enough)