Cave Story 0.1Free
Cave Story is really one of those games that can be considered a masterpiece of game design. There are so many wonderful and classic gaming elements, that I cannot even begin to describe just one quality well enough to say "It is for this one reason alone that Cave Story is a great game." There is just so much effort, originality and ingenuity behind this game and it really shows more and more as you play through it.
The developer, Pixel spent five years making this game as fun and as great as it is by adding solid controls, smooth gameplay, a great cast of characters and dialogue, an interesting plot, good music and beautiful old-school 2-D artwork. And on top of all this added multiple endings, several boss battles, tons of items to collect, all kinds of added secret bonuses and special challenges, various and considerably different methods of playing through the game depending on your actions, competition ranking features and an extremely high replay value. For a freeware game it is fairly lengthy too. Cave Story is by far the best freeware game I have ever had the honor of playing through and certainly one of the best games I've played.