How can I check how many enemys are alive in area ?
I tried Number of units in (Units in myarea<gen> owned by Player 12 (Brown) but after I kill all the units there number of units doesn't change (it change only when I spawn enemys, but never decrease)
You can add an If/Then/Else to your Pick Every Unit action, or replace the Units in Region Owned by Player with Units in Region Matching Condition and use an And condition to check for living units as well.
By the way, you're leaking a group variable there.
I'm on a page about incorrect corrections, and spent the better part of like two hours trying to get someone to understand that -5^2 = -25, not 25, and then that post had comments get reposted because that group is self sustaining, and that person was in turn trying to explain what I just explained to them. And I'm taking that as a victory