The first boss is Gooseka and he will be very easy to take care of.

First, the Jan Ken Po.

We play Rock, then Scissors, then the fight starts.

Rush over to Gooseka and repeatedly punch him. The second you see a blue orb, step slightly to the left and it will bounce over you. Run in to finish the job. If you're fast enough, you can finish him before the first throw of the blue orb but it is not worth the risk.

Next up is Chokkina.

For the Jan Ken Po, play Scissors and Paper.

The fight is another spam but this time we look above him. He'll drop rocks down which will stay on the ground. He does NOT always drop a rock above you, so we can just keep attacking and finish him off with luck on our side.

If not, be sure to dodge his attacks while keeping an eye on the exploding rocks on the ground.

Next is Parplin. This will be a little trickier than the others as he's quick to bounce around.

Just like Gooseka, Rock and Scissors will get you into the fight.

Parplin will instantly bounce to your half of the screen so try to get under him and wait for him on the left side. If you're feeling confident, you can hit him and wait out to see if you're required to move, as clouds with lightning will spawn in random parts above you. The safest bet is to let the lightning strike first and get your hits in.

It will take longer but the only real risk in this fight is the random lightning. I also like to try to get a few extra hits in as he lands between his jumps but it's also risky and he's faster than you'd expect.

Janken the Great. The final boss and also the easiest once you figure out this trick.

Get the Jan Ken Po out the way and play Paper twice.

Now get ready for his wave attack. Dodge the first one and immediately run in. You want to position yourself at his feet, between the spikes above you. His next wave attack will start OVER your head and completely miss you. The spikes, if they choose to come down at your location, should also miss you.

The final, the easiest with this technique and the achievement is now yours!