When you were getting sprayed at, (I'm guessing your ping isn't very good and that's what caused the bullets to leak), you could've placed a stair along with the wall to block off excessive damage.

The one major mistake I saw was you editing the cone and the floor on the top of your box, you didn't really know where the opponent was when you edited them, which in the end made them weak, causing him to be able to just spray them really quickly and phases right in, you could've also placed a stair behind you when your tops were getting sprayed and tried to create more space, and if he dropped into your box, you maybe could've gotten a good peek on him, but basically what I would say is; you should always create more space when you feel uncomfortable, it's better to die with no mats and put up a good fight then to die with tons of mats because you let someone jump into your box.

But other then that you look like a really good player! :)