This just my ranty two cents about Volcano.
The entire rest of the game I was able to gold medal by myself/with other people on co-op. The 3 "hard" levels before Volcano...the final Vlad fight...all able to be done with just one person.
So why is Volcano such a pain in the ass? Who knows!
Single player I can make it to the final wave with between 90-85 percent left, and then out of nowhere something explodes/shoots right at the end, and cuts out like 10% base health out of nowhere. Same thing happened tonight, twice, doing 4 player co-op. Our best run had 90+ percent going into the final wave, and right at the end the base meter flashes red and drops past the "gold" level.
So yeah...F you Volcano