SC1 UMS maps like Turret Defense in Space and Lurker Defense (I can't find the original anywhere) are actually what got me into mapping in the first place, years back.
I wanted to create a Lurker Defense map because there are none on the arcade at the moment and that is a tragedy! I set about creating a new Lurker D map, trying to preserve the simple style of old school defense maps (even before tower defense was a thing!) while introducing some new concepts that I think add to the fun and strategic depth of the map.
In the original map, it was simple. Don't let any terrans or protoss get by or you lose! FFA survival. This map is also FFA survival, but you get 50 lives. You can also upgrade your Hydralisks into more than just lurkers, I've added Hunter-Killers, Baneling Launchers, Infested Marines, Sniperlisks, and Kerrigan.
Other than that, its pretty straightforward, simple - but hard to beat! I have only gotten to level 35 out of 40 so far. Let me know if you manage to finish it. GL HF!