Wow... I didn't even know you could shoot UP until after I'd escaped.... escaped without getting the core. Definitely changes the tone of the game- would suggest making an alternate ending for completion both with and without damaging the core.
Only thing I would change is allow to toggle off "Use player names" in creation screen. Some people abuse that feature, and you end up with a ridiculous game using only people's "dirty" names.
Good concept- play gets a bit repetitive at times. If you could, set up the 'special events' so they pop up with a box you need to click to clear, as I accidentally closed the events trying to level and missed some story. Further, there's some spelling/grammar issues that can be a bit jarring at times. All in all, though, good fun. 4/5 (oh, btw... Poison Clan rules!)