HAYAI – a slasher video game where the main goal is to collect as many points as possible. There is no plot as such, only a brief backstory. The main characters are five ronin, samurai who have lost their overlord or somehow disgraced their master's honor. As punishment, they were deprived of their former status and all privileges, and now anyone can try to finish them off. The key word is “try”, since the warriors are not at all going to accept their fate with submission.

Thus, the goal of the HAYAI gameplay is to hold out as long as possible, destroying one wave of enemies after another. Enemies die with one hit, but so do former samurai. To increase the heroes' chances of survival, the developers added special skills to each of them. For example, all playable characters can defeat multiple enemies at once. In the gameplay, this is implemented as follows – the scene freezes for a short moment, allowing you to draw a line with the mouse from the character to the enemies. After that, the protagonist destroys the enemies with lightning speed in the way the gamer drew.

In addition, the characters have individual skills that add variety to the gameplay. For example, one ronin can summon allies for a short time, destroying all enemies on the map. Another is armed with a giant hammer and when he strikes, he creates a shock wave that destroys all enemies. The longer the warriors stay alive, the greater the reward the gamer will receive when the warriors finally die.