still able to target defeated monsters

[Maladjusted_Miasma]

they dont dissapear in areas like the saw mill and katsumis doll. they just sit there. by the end of the mission, there are 10+ of them sitting around... this has been happening for a while now....

[Lady Saxophone]

Sounds like you have problems with ghosts.
When you try doing something to them, does the system give you a message above the animated saying "Invalid Target"?
If so, to fix it, just refresh the game or change screens.

Invalids appear when you have bad lag. Make sure your graphics are on Low and animations are set to Self-Only.
(Game Menu > Options > Graphics Options)
If that doesn't help, there's nothing else much you can do besides maybe clearing cache and making sure your browser and flash player are up to date.
(Or consider Ad-blocking zOMG!)