The P99 is a unique pistol. And although this simulation shows the decocker button, tapping it only racks the slide. SonIm not sure if there are other inaccuracies as well.
Do you want to know how does Walther P99 pistol work? 3D model with animation explains Walther P99 function! What is inside the app?! - High detailed 3D model - Operation animations: fire, unload, reload - Additional: backstrap, slide alternative color, frame alternative color - Augmented reality (use your camera to take and share AR photos) - Slow motion - X-ray mode - Cutaway mode - Tap'n'Hide mode (hide any part of the model, just tap it)