For some reason I thought DS2 has 12 levels.  So when I reached level 13 it was a bit of a surprise.  It's getting tough now, with all the "black" variants of the enemies.  But the combination of Ripper, Line gun and the Plasma Gun seems a reasonable set for most occasions.  I've not bought a large number of the guns, saving money for Power Nodes, and upgrades.  So the second run through to mop up achievements, I'll try some of the other guns out.  Better story than the first game, certainly, but not as many memorable boss fights.   
 
Overall it's a definite improvement over the first, which itself was one of my favourite games of the past few years.