Co-op maps?

FlavorRage

L4: Comfortable Member
Oct 12, 2008
197
57
Anyone remember the old Area51 maps for TFC, or the JSC ones for HL2DM? Those were so much awesome fun. I'm working on a small project that I may or may not release, and I was wondering if anyone could guide me to a tutorial on how to make an object that will shoot at you until a brush is destroyed. I know you can place sentries, but I'm not sure if fighting nothing but sentries would be any fun. Also, are there any co-op type maps out now? Thanks in advance! :)