Nice and small. A couple sniper areas. More slime passageways than the first. More secret sniper areas. Another awesome vdeth level.
Secrets abound, as always.
By far the best feature, however, is the invisible fort. Protect yourself from incoming weapon attacks with the security of a totally transparent and invulnerable wall which you can raise and lower instantly at your whim. The largest of the vdeth levels. It's a constantly moving elevator room with lotsa goodies inside. Many secrets in this level.