New level "Thriller Night" (beta)

I just finished the Halloween special. It is called "Thriller Night" and Michael Jackson is in it . New game mechanic: protect and herd farmers , save them from turning into zombies and escort your humans to rescue zone (a schoolbus) .

Also removed all unachievable achievements and coded McSamurai, so now you can reach 100% achievement.

If you want to test drive the new level, it's in the beta branch. right click mcdroid > properties > beta