Don't mistake the title for a zig-zag, this is actually the title of a game.
Everyone has played at least one retro platformer. If you like retro platformers and you don't mind a challenge you'll probably love VVVVVV. Two things strike me about this game, it is difficult and the world is strangely open, you wander around this open world looking for levels to go through. Your main purpose is to find your missing crew members, and as a secondary goal there are round shiny things that you have to pick up.
Since the game is so bloody difficult, you have an infinite amount of lives, the challenge here is not beating the levels with a given amount of lives, simply getting through the levels is not the challenge, nothing so vast. No, the simple challenge lies in getting from checkpoint to checkpoint.
Other than possibly The Impossible Game on Xbox 360's indie games, I have personally not played a harder retro style platformer, and I don't think I'd be able to stick to one, I am honestly proud to say I beat the main world on VVVVVV but never really touched all the additional side worlds they give you. If you love a challenge this game is for you, if you get mad when you die a lot, then I suggest you either play this game when you're calm or just stay away, either way, a great game and everyone should check it out if they haven't already.