Way way way too easy (esp. the last boss) . . . the eyecandy is nice . . . however, now I wished that they waited to release the entire game for $40 instead of 3 installments over 3 years for $60 . . .
I really liked SS#1 - that Bad Boss was a real challenge compared to SSSE's Mr. Summoner (just keep the heaviest firepower concentrated on him while avoiding enemy hits) . . . I got him on my first try . . .
Fortunately, my notebook's (16MB DDR) ATI Mobile Radeon IS able to play it at a decent framerate with all details maxed @ 800x600 and 32bit color.