I had plans. But the plans went out of the window a few times. Mostly due to non-development related things.
The plan is to have the release version with rich roguelite mode + one story mode and after that to expend with new zones, enemies, items and new stories (these are meant to be 1-2 hour long modes that resemble traditional single player games).
You can push them of the ledge or use grenades/mines. Right now I am changing weapon system and one of the possible improvements for guns is "armour piercing" node. Also there are going to be other types of weapons. And traps. So there's going to be a plenty of ways to dispose enemies.