I'm sure I'm wrong, but like everyone else, I like to speculate.......
I agree with others here who think we'll have a 3 minute game. The hint may mean nothing more than that. Just like FIRST to float a tiny tidbit. A longer game may mean a more complicated task, like gathering and/or stacking.
I did a little research into early PC games looking for anniversaries. Turns out that the predecessor to Minesweeper was called "Mined Out" and released 30 years ago, in 1983. So, there's your "water" reference
Some might say we're due for a unique gamepiece, maybe like the tetras from the past, or another shape constructed from PVC. Imagine collecting or stacking gamepieces for points, while avoiding the "hot" mines. If you really want to get crazy, you could make the "hot" mines a Roomba. Contact with a "hot" mine would mean having your robot disabled (by means of the infrared remote) for a period of, say, 15 seconds. Another good reason for a longer match?