ILLEGAL: N d1-c3 on turn 5:
There was no N on d1. The piece on d1 is a K.
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For diagnostic purposes, here is the full movelist:
1. P g2-g3 
1... p c7-c6 
2. P f2-f4 
2... b d8-b6 
3. P d2-d4 
3... p e7-e6 
4. C c1-d3 
4... p f7-f6 
5. N d1-c3 
5... b e8-g6 
6. C d3-f3 
6... n g8-e7 
7. Q b1-c1 
7... p h7-h5 
8. C f3-h4 
8... n e7-f5 
9. C h4-g6 
9... c h8-g6 
10. S e1-d3 
10... b b6-d4 
11. Q c1-d2 
11... b d4-g1 
12. R f1-g1 
12... s f8-b6 //f8-d8-b6
13. N c3-e4 
13... s b6-d2 //b6-b4-d2
14. resign
In case there is a bug in the code, the settings file can be edited at /play/pbm/play.php?game=Cetina+Random+Chess&settings=asymmetric&submit=Edit