It's just a graphical glitch when in Splitscreen mode. Some textures don't look the same, or disappear when other textures are used. It prevents heavy Frames Per Second drop.

Original_Sin wrote It's just a graphical glitch when in Splitscreen mode. Some textures don't look the same, or disappear when other textures are used. It prevents heavy Frames Per Second drop.

I'm thinking this is the correct answer. I was playing down in our media room on a 120" 1080p projector. I tried last night on a 52" LED to reproduce what had happened, and I couldn't.

The only thing that made me think maybe I had done something was all the power-ups that dropped right in a row. I couldn't get that to happen again either...

SanPatricio wrote
The only thing that made me think maybe I had done something was all the power-ups that dropped right in a row. I couldn't get that to happen again either...

It's all random. Sometimes when I'm running a Zombie train and get a lot of quick kills, they'll drop 3 power ups simultaneously or within 10 seconds of one another.

I've even hit a Nuke before, and had 3 of the nuked Zombies drop power ups.