Save the Ninja Clan (UP)

Simply die 25 times. Every time you will respawn at the start of the level for you to die again. Above your head at the start of the level they show the number of attempts making it easy to see how far you are on your way.
I picked level 3 and just kept the left stick to the left for a couple of minutes making my ninja guy run into water the entire time, dying and respawning. After that *ploink*. Continue doing this if you want the die fifth times achievement. And we all know you do...