I'm looking for help identifying a game we used to have when I was young. This would be in the mid 80s, I think. We had a box of big floppys with a few games on each. One game was simply called "Spider.EXE". (I think. I could be wrong on the name)

The game was a single screen/box/room with a dude in the middle standing in the floor. Spiders would begin to drop down on a thread of web. The guy could move to the left or right. He had a gun, but could only shoot straight up. He had to shoot the spiders before they reached the ground. If a spider reached the ground, the web thread would become thicker and function as a wall making his room a bit smaller with less room to run. The grounded spider would, then, crab walk towards the guy. At this point, the guy could only stomp left or right at the spiders, killing them.

The spiders would keep coming, faster and faster, more and more. The game would end when I spider got to him without being killed. Googles have failed thus far.

Here's a shoddy example