[invalidfunction]

It's minesweeper, not an enterprise storage server. Spending 3 hours planning minesweeper would be insane. Heck even planning for more than 20 minutes, in my personal opinion, is overkill. You should be able to at least get started before the 30 minute mark and if you spent half the time planning should be close to being done before the end of the hour. At the end of the hour, just explain what you have left to do.

[yeukhon]

I don't know how to play minesweeper, so how on earth am I supposed to solve it in 30 minutes? Looking up the rule in 30 minutes? I don't know how to play Sudoku either. DO you know how to play Go? Can you implement that in 30 minuets? Do you know how to play Mofoka? Of course you don't know Mofoka I just made it up. Please think about how ridiculous it is to ask someone to implement a game in an interview.

[emerongi]

I'd expect the interviewer to explain the rules beforehand, probably even show the game quickly. That way everyone starts off with the same amount of knowledge about the game and then it's all about programming.