Anyway. It is almost impossible for me to say anything about this game that you haven't figured out from the title. You have to find an eccentric millionaire's will. He left it in a safe. One of about thirty safes, vaults, doors, and other locked sundries which are scattered around his mansion. By the time you reach the end, you will have unlocked them all.
Like its predecessor, Safecracker 2 is made up of logic puzzle locks and combination/key locks. Unlike in its predecessor, the logic puzzles predominate. You will see lots of variations on familiar types: rule mazes, sliders, jumping dots. None of these are particularly hard variations. (Which is good, because who wants to solve a hard slider puzzle any more?) Most of them are at least slightly creative variations. (Also good.)
(One game-mechanical quibble: if you're halfway through solving a puzzle, and you step back or move away, the puzzle resets. Be warned.)
Do not expect to spend much time looking at the scenery. There is scenery -- it's a nicely-rendered mansion, albeit a bit sparse. But nearly all of it is backdrop. There are a couple of visual clues hidden in the mansion, but mostly it's stuff you stroll past on your way from one safe to another. You won't even get lost; you get a dynamically-updating in-game map. Handy, but it pretty much kills any need to think about the environment.
A quick litany of other game elements which were not exciting: the music. (Repetitive.) The narration. (Smug. You mutter to yourself a lot, which can be a nice way to keep you oriented in a puzzle, but this version seemed mostly random and unhelpful.) The story.
There is, theoretically, a story. You encounter letters and postcards throughout the mansion, from which you learn about the various family members who stand to inherit the loot. This does not affect the gameplay at all. It shows up, interestingly, at the end -- you find the will, and (spoiler, la la, sorry but this isn't a major part of the game) you get to choose who inherits. It's like having multiple endings, but -- it doesn't play like multiple endings, because it's so clearly separated from what the game is. Instead, it comes off as a reward: you've won the game, now you get to point the magic wand!
I am not disparaging the idea, actually. It was a reward; I got a couple extra minutes of enjoyment trying all the choices. (Save before you open the final safe.) Player choice can be fun even when it's not a "YOU control the story!!" situation; this was a nice demonstration of that. But it still leaves the narrative content of the game as "puzzles, go at it until you're done." Which is disappointing in this day and age.
Now I have described the whole thing. Summary: puzzles, lots of them, not too difficult. Go at it.