Nickelodeon All-Star Brawl

All of these Sports games and achievements are accessed through the Battles option from the main menu, then choose Sports. Once you get to the character selection screen, press  to open the Rules. In here, make sure the game type is set to match the requirement in the achievement description (for example, plankton ball, football, etc.). Set the match to end when someone reaches 15 points (that's the default, but you could lower it if you want, as long as it's at least 10 obviously). It doesn't make a huge difference which character you pick, but I recommend someone with good reach/range. Catdog was my character of choice, because its  attack reaches far and wide, and its  attack shoots a ranged weapon. As for your opponent, choose a slow character with not much reach. I always chose Spongebob or Patrick. Obviously make sure to lower them to CPU level 1 so they're as easy as possible.

As for the games, despite being called different things, they basically all play the same way: you play on a level of your choose like normal, but behind each player on each side of the level is a goal (shaped like a star) that you need to hit the ball into. The ball (re)spawns right in the center of the level each time. As the achievement descriptions say, you need to win each type by at least 10 points. By default, unless you lower it, the game will end automatically when 15 points are reached. This gives you a buffer of five points in case your opponent manages to score on you. Once you get going, it's pretty unlikely your opponent will score more than once, so feel free to lower the max score from 15 down to 11 or 12 if you're more confident. It only saves you a few seconds anyway.

The general strategy for each game type is exactly the same: pick a flat simple level (such as the first one, the Spongebob one) so that you can just hit the ball forward into your opponent's goal. What you're going to do is alternate between hitting your opponent with  to knock them away, and then hit the ball toward their goal with  to score. If you hit the ball right from the center of the level where it spawns, it'll go right into their goal every time. Just keep your opponent away by either alternating hitting them and the ball, or just hitting both at the same time. Once you get the rhythm down, you'll be scoring every few seconds, as soon as the ball respawns.

The only exceptions to this are:
 

• In football mode, you actually have to pick the football up with  and throw it with the same button, rather than hitting it. Strategy is the same though: alternate between hitting your opponent away with  and grabbing/throwing the ball with  to score. Like with other modes, I was able to throw the ball right from the center where it spawns and it would perfectly hit the goal every time
• In plankton ball mode, the ball is bigger and as different physics that the others. I ended up needing to use  attacks to move it forward properly to reach the goal, but the overall strategy is the same. Try  attacks first to see if they work for you like the other modes though