I found this sequel as good as X-Com 1. I would even say that it's a *little* better ... Sure that it's just under water and there not as much battle on the ground, but the advantages (more crafts, weapons, technologies, and graphics a little better) surpasse the disadvantages IMHO. I've finished the two games !
It's my best DOS game of all time with X-Com 1, King's Quest 6, Space Quest 5, Goal, Little Big Adventure(!), Privateer(!), and Lands of Lore(!). The last one is ssooo good !!! But warning ... it's too addictive !