Today it's World's Hardest Game. Now, I'm not saying this is the world's hardest game. It's not that it's not challenging, it is, but that's the title. I'd say it lives up to it pretty well. My only tip is patience. You're scored on deaths, not on time.
This game was made by Snubby Land. They have some other games on there too. I rather enjoy the hand drawn graphics on Super Tank.