Arguably the most well-known indie game of all time, Cave Story+ features a completely original storyline wrapped with personality, mystery and hours of fast-paced fun. Cave Story+ is an action-adventure game that is critically acclaimed indie game. Overflowing with unmatched charm and character, Cave Story+ takes you into a rare world where a curious race of innocent rabbit-like creatures, called Mimigas, run free. Run, jump, shoot, fly and explore your way through a massive action-adventure reminiscent of classic 8 and 16-bit games. Cave Story+ features higher resolutions, tons of new art and music, along with content not available in the original version.
I not played this game yet, but here it's free and in Steam - $9.99. Thats not so cool :(