Rented a specific bike so I could take an extended test ride, and the bike shop that rented it to me should be ashamed of themselves.
The chain skips in a couple of gears, but a bit of barrel adjusting seems to have fixed that.
The danger though is that the cranks lock up due to the chain binding on the rear derailler randomly when I shift to the highest rear while on the middle chainring. Fortunately the times it did this I did not go over the bars or otherwise have an accident, but I was just lucky.

I really can't believe a bike shop would rent out a bike in as poor a shape as this one is in...there's just no excuse.

I'll surely be cluing them in tomorrow when I take it back, but it's probably wasted breath.