Part-action, part-puzzle, all old-school challenge.
Essentially, Solomon's Key is all about going through different stages, finding keys, and then reaching the exit. To do that, you're going to have to avoid enemies and make your way around the maze-like designs of the levels. This is made trickier by the fact that taking any hit is an instant failure, making you restart the level. However, you do have a few tricks -- fireballs that eliminate enemies, and your main ability, creating and dispelling magic blocks. Using this power, you'll block off enemies, create pathways, and find your way to victory.
In addition to finding the key and getting out of the stage alive, there are fairies which can be rescued, leading to secret stages and even alternate endings, a rarity for such an old game. However, lounging around is not encouraged -- a timer counting down to your demise further adds to the difficulty.
Graphically, this is a NES game, and a fairly typical one at that. Don't expect to be wowed by flashy effects, as this game exemplifies the old-school mentality (by our standards) of stripped down visuals and ramped up difficulty. Sounds are nothing amazing, but the background music can be catchy at times.
With so many stages, an interesting gameplay mechanic, and graphics that get the job done well enough, Solomon's Key is a good bet as a download on the Virtual Console. That said, the game will certainly appeal very much to one crowd and seem irritating and obscenely difficult to another. If you're the type who enjoys perplexing puzzles and tricky action, Solomon's Key is right for you -- it successfully marries these two types of gameplay into one satisfying game.