Depends upon the puzzle. They can represent 0 in puzzle like Slitherlink.
They cannot be 0 in puzzle like all-seeing snake.

Please check this post and Vladimir's reply too.

Happy jubilee, Vladimir!

Very nice puzzles! I had a bad start and with one mistake I could not finish the first sudoku. It took me another 50 minutes to complete the test.

Nikola

So it's a hard test for me. First submission in 50 minutes or something, that's after a first go looking at all and failed to find the solution. I started to go trial and error (or look ahead?) and it worked pretty nicely for 8 puzzles (the rest I didn't have time :P ).

Nice test though. If Fillomino Cipher had appeared, I would probably solve those right away, but it seems like people are sick of Fillomino after FF2 :P

How balanced do you think the puzzle types of this test were?	Fairly balanced
What was your opinion of the distribution of easy/hard puzzles?	A bit hard
What did you think about the puzzle quality of the test?	Very nice
What was your opinion about the answer key extraction?	Perfect answer keys
How did you feel about the length / time limit for this test?	Just right
What was your opinion of the booklet formatting and printing?	Just right

How balanced do you think the puzzle types of this test were?	Perfectly balanced
What was your opinion of the distribution of easy/hard puzzles?	Just right
What did you think about the puzzle quality of the test?	Very nice
What was your opinion about the answer key extraction?	Mostly perfect answer keys
How did you feel about the length / time limit for this test?	A bit too many puzzles
What was your opinion of the booklet formatting and printing?	Too few pages / too small grids

How balanced do you think the puzzle types of this test were?	Perfectly balanced
What was your opinion of the distribution of easy/hard puzzles?	A bit hard
What did you think about the puzzle quality of the test?	Average
What was your opinion about the answer key extraction?	Perfect answer keys
How did you feel about the length / time limit for this test?	Way too many puzzles (too little time)
How fair do you think the rankings were?	All players got the score they deserved
What was your opinion of the booklet formatting and printing?	Just right

How balanced do you think the puzzle types of this test were?	A bit skewed
What was your opinion of the distribution of easy/hard puzzles?	A bit hard
What did you think about the puzzle quality of the test?	Fairly Nice
What was your opinion about the answer key extraction?	Mostly perfect answer keys
How did you feel about the length / time limit for this test?	A bit too many puzzles
How fair do you think the rankings were?	Most players got the score they deserved
What was your opinion of the booklet formatting and printing?	Just right

How balanced do you think the puzzle types of this test were?	Perfectly balanced
What was your opinion of the distribution of easy/hard puzzles?	A bit hard
What did you think about the puzzle quality of the test?	Fairly Nice
What was your opinion about the answer key extraction?	Mostly perfect answer keys
How did you feel about the length / time limit for this test?	A bit too many puzzles
How fair do you think the rankings were?	Most players got the score they deserved
What was your opinion of the booklet formatting and printing?	Just right

How balanced do you think the puzzle types of this test were?	Fairly balanced
What was your opinion of the distribution of easy/hard puzzles?	Too many hard puzzles
What did you think about the puzzle quality of the test?	Average
How did you feel about the length / time limit for this test?	Way too many puzzles (too little time)
What was your opinion of the booklet formatting and printing?	Just right

Solution booklet

The test is over. Thanks to all the puzzlers for participation! Special thanks to Nikola for the congratulations :)

TOP 3:
1. Kota Morinishi (JAP)
2. Hideaki Jo (JAP)
3. Palmer Mebane (USA)

It was a very impressive performance from Kota, with just the bottom All-seeing snake unsolved. Congratulations!

Some statistics:

- The puzzle solved by least competitors (aside from Classic Sudokus) was the same bottom All-seeing snake. It was solved by 12 competitors.
- The puzzle solved by most competitors was top Four winds. It was solved by 89 competitors.
- The puzzle with the highest rating was bottom Futoshiki (8.83) and the puzzle with the lowest rating (again aside from Classic Sudokus) was top Sudoku difference (6.62), which is pity as it was the first puzzle I've created for this set and it led to the whole thing :)
- The puzzles submitted with the highest/lowest accuracy were the Classic Sudokus - top (100%, 3 out of 3) and bottom (40%, 4 out of 10)

I'm sorry for the fact that broken Slitherlink puzzles appeared in the original booklet (had multiple solutions, all the solutions aside from the intended ones were accepted) and we had to upload the new booklet during the contest. I believe it had no significant impact on the table of results.

See you next year or even earlier :)

All the best,
Vladimir

Congratulations Kota for the very impressive win. That makes it 2 in 2 months.