**Solution for people who have 2 controllers**
Easy achievement, took under 10 minutes to complete.
The other solutions are sufficiently explanatory, but here is one for those who are completely unfamiliar with the game and how it works.
1. From the Main Menu select VERSUS
2. Select the first option (TEAM VS)
3. On your 2nd Controller- Press Start and go Right on Analog Stick to assign it to the Player 2 slot
4. On your 1st Controller- Go Left on the Analog Stick and Press A
5. Now you are on the Character Select screen -
6. On your 1st Controller- Mash A (you need to press it 7 times), until it says "COMPLETE" in green text on the left side of the screen -- OR press it 6 times and then select Level 5 for player 1, I haven't tested this but it SHOULD work fine.
7. On your 2nd Controller- Press A six (6) times / until you have the option to select a level. Go down and select Lv1 HP 50% and press A
8. On your 1st Controller-hit Y and then A
9. On your 2nd Controller- hit X and A
10. On the Stage Select Screen, On your 1st Controller- hit A
11. Now use your 1st Controller to defeat the opponent. Do this until you get to the Results screen where you will have the option to RESTART-- select RESTART -- complete this process of defeating the enemies and restarting 3 times and the achievement should pop immediately.