This gamemode was added as part of the Hellboy crossover.
An achievement can be earned by completing wave 25 in this game mode.
The Horde gamemode is notably a Player vs. Enemy gamemode, where players must work together to defend Horde enemies from breaking the two gates on the map. The match is separated into waves, where each wave Horde enemies will enter the stage in different formations. The match goes on indefinitely until the game is lost.
There are three types of horde enemies:
- Blue enemies, which are the most common enemies and take only one light attack to be KO'd
- Yellow enemies, which are similar to blue enemies but a lot faster, begin spawning on wave 6
- Red enemies, which are slower but take more damage, generally taking one heavy attack to be KO'd, begin spawning on wave 11
Each of the horde enemies are flying enemies that target the two gates on the map. The more enemies hit the gates, the more damage the gates take. If the gates take too much damage they will open, and if any horde enemy enters an open gate the match is over. Each gate opens after exactly 24 enemies have entered it, and the 25th will end the game.
While the goal of this gamemode is to get to the highest wave, the winner of the match is sometimes determined by who KO'd the most horde enemies.
Most waves consist of random enemies spawning, but some have a specific pattern. Their difficulty will vary based on the number of players in the team. The table below describes them. If a wave has no information it means the spawns are random or no special pattern was noticed, but the frequency and amount can vary. You can watch footage of the waves on videos submitted to speedrun.com's Horde Mode category.
|1||Enemies spawn from the sides in two different heights, moving towards the door on the opposite side. A few enemies also come down from above.||B|
|4||Enemies will come from the left and the right, in two different heights, where the lower ones will head towards the closest door and the higher ones will head towards the opposite door. The left enemies spawn first, then the right, and then the left again. The left side will have more enemies overall.||B|
|5||Gruagach spawns; Enemies stop spawning once it is defeated.||B|
|6||Fast yellow enemies are introduced. Spawn one by one from random locations, some headed towards the closest door and some to the opposite side.||B Y|
|7||A large amount of enemies spawn from below between the two doors, in 3 columns. A few yellow enemies might instead come from the bottom corners, headed towards the closest door without passing through the middle.||B Y|
|9||Many yellow enemies will come from the top down in a space-invaders fashion moving down-right-down-left-down-right-down into the right door. If there are more than 2 players, a second stream of yellow enemies will follow, from the top right going down-left-down-right-down-left-down into the left door. A few blue enemies spawn at the end.||B Y|
|10||Gruagach spawns; Enemies stop spawning once it is defeated.||B|
|11||Red enemies are introduced, spawn randomly and go towards the closest door.||R|
|12||15 red enemies will come in a wave pattern from the left side, and if there are 2 people they will be more spread out. Blue enemies will spawn randomly from the top throughout the wave, frequency depends on team size.||B R|
|14||For each door, a stream of red enemies will come from directly above it, and if there are more than 2 players then there will be a second stream from the sides. For 2 players the top streams consist of 8 enemies, for 3 players the top streams are 5 and the sides are 3, and for 4 players all four streams are of 5 enemies.||R|
|15||Gruagach spawns; Enemies stop spawning once it is defeated.||B R|
|16||B Y R|
|17||Two streams of yellow enemies will come from the top middle, and will go in a heart shape curve towards both of the doors.||Y|
|18||B Y R|
|19||Red enemies will come from the right in a straight line, followed by a line of yellow enemies which go towards the left side of the screen and then come back facing to the right for a second chance to kill them.||Y R|
|20||Gruagach spawns; Enemies stop spawning once it is defeated.||Y R|
|21||B Y R|
|22||Five enemies come at once to form a pentagon in the middle and then spin around in a circle, and after one lap they go towards the nearest door. The first ring is 5 red enemies, then blue, then yellow. For more then 2 players there is a second yellow ring that follows.||B Y R|
|23||The enemies spawn at random but come mostly from the bottom.||B Y R|
|24||A flock of many red enemies will come from the top left corner, heading to the center and then most turn around to reach the left door. A flock of many yellow enemies from the top right corner closely follows, heading to the center and then to the right door. Then again a flock of red from the left and another yellow from the right.||Y R|
|25||Gruagach spawns; Enemies stop spawning once it is defeated.||B|
|26+||Rounds become random and more difficult as the game goes on. No more Gruagachs spawn.||B Y R|
Note that the game can go on forever, but there are no special patterns after this point.