Brawlhalla

As the achievement states, you only need to reach wave 26. You must complete wave 25 and then your achievement will unlock upon wave 26 starting.

How to Set-up the Lobby: You can use a private custom lobby for this achievement or public custom matches for this achievement. Just remember that it always needs be hoard with 100% damage (default) and change the time to 15 minutes.

Before Attempting: Through trial and error, I've found that doing this with only two people is easiest. You cannot do this achievement solo and doing it with 3 or 4 people adds more enemies and makes the whole thing harder. You shouldn't use bots at all because the bots are terrible. You should also play with someone who is familiar with the game. Both players should be using characters that have quick and large area signature moves. The best characters I've found for hoard are Queen Nai, Mirage, or even Hattori. Queen Nai is best however because of here neutral signature on daggers is perfect for hoard. You should also use the dexterity stance so you can get moves out faster.

In-Game: You and the other player should cover both portals. Kill all the enemies as fast as you can. If you don't have any enemies on your side, maybe help your teammate out. On boss waves, one person should be focusing on the boss and the other should be killing all the additional enemies. However, the quicker you kill that boss, the less adds you have to kill.

It really is straight forward. I've heard of ways to cheese the boss enemy and quick kills on him, but never found a strategy that consistently works. It's all a matter of trying to remember as many of the waves as possible and how to beat them taking minimal hits to your portal.

If a particular wave is giving you trouble, refer to this video: https://www.twitch.tv/videos/409124953
It features one of the top pro players and a caster for the esports.

Hythal's guide above is excellent if you want to do this achievement "legit" however there is a cheese method and I've already helped 2 groups with it, with 2 people in those groups unlocking it as their first achievement.

First off credit for this solution goes to LD_Magister who posted it on TrueTrophies as well as for making the video.

The video itself has text but here's the basic solution so go to custom game and select the horde mode.

There are 2 doors to defend, and the amount of enemies that are allowed to hit the doors are somewhat little, about 25 and you're out. The trick is to play as Queen Nai as her katars neutral signature (pressing Y/B while standing still) sends her up into the air with a massive rectangular hitbox which will hit every enemy during the entire animation so long as you stand in the center of one of the doors. Unfortunately this method only works with 4 people however you can have 2 people with 2 controllers alternating who presses Y/B but will be a little more difficult. This achievement becomes nothing more then pressing a single button and keeping a rhythm with the other person at your door and all the difficulty is just turned into luck on whether any enemies get through your timing.

Things to Note:

• A bot will spawn every so often, just ignore him and continue the rhythm, he will walk into your attacks eventually and you won't have to worry about him. There is a chance he may hit you away from the door, just recover back to it and continue using your sig.

• Waves 17 and 22 seem to be the hardest so really focus up on those as a single slip of the rhythm can destroy an entire door from 0 to 100.

• Queen Nai costs 2300 coins in the store which shouldn't take no more than an hour if you're just starting out otherwise purchasing the legends pack will give you her and every other character immediately.