How do I make Xonix game?

Hello, I want to create Xonix as mini-game for my game project. Xonix is a game where player should fence off sections while trying to avoid enemies (https://en.wikipedia.org/wiki/Xonix, archive.org/details/msdos_Xonix_1984).

Despite the fact, that this game is pretty simple, I can't figure out, how to implement it in Construct.

Xonix consists of

1. Player, that can move in 4 directions (using 8-direction behaviour)
2. Game territory, that should be fenced (I have no idea, how to paint area, when player draws a line from one point to another)
3. Enemies (that's pretty easy, they just randomly floating or moving towards player)
4. Score system, that determines how much territory has been captured

Could you please help me with this?

Thanks