I did enjoy this game but i was expecting a bit more. In the end of the world games i think Fallout set the benchmark with something for everyone and every style of play, maybe thats why i didn't like it as much.
The graphics and gameplay were brilliant, the main problems i had were that the game never really evolved you fought the same soldiers and monsters throughout. Also you had for the majority of the game a set route and were not free to explore (the limitations of the underground i suppose). I found it too short aswell.
It was sill a very good game i just found it very limited in a time where games are opening up gameplay and freedom.