would it be allowed, there's sound and noise

Recordings are usually recommended to be in one video for speedruns to avoid splicing and such. Also, if you are looking for a way to record gameplay without a capture card, you could always use a webcam and point it towards your screen, as long as the gameplay is visible it's acceptable.

"there's sound and noise" - smocesmoce 2020

no it would not be allowed

yeah, there has to be a continuous recording