It's difficult. Generally, waves sorta go in threes. Rooms spawn a set value of enemies, each enemy has their own value (armored versions being worth more). Once the room value is reached nothing spawns anymore. And it spawns those enemies in waves. It's a bit of a guess when you're at a last wave, but if you keep playing you'll also start noticing that you can sort of sense a room has to be done by a certain point, and you'll be right about that more often.
Nice video, may I ask when do you know its the last enemy
It's difficult. Generally, waves sorta go in threes. Rooms spawn a set value of enemies, each enemy has their own value (armored versions being worth more). Once the room value is reached nothing spawns anymore. And it spawns those enemies in waves.
It's a bit of a guess when you're at a last wave, but if you keep playing you'll also start noticing that you can sort of sense a room has to be done by a certain point, and you'll be right about that more often.