I'm planning to try some 10 courses runs. In those, the competition can be in milliseconds so more accurate timer operation timing is needed for me.

【Timer Start】 The timing of pressing the [A] button at the start of the game and the timer start often faster/slower from each other. In order to check whether the timer started timing is accurate, I think it's good to calculate based on the timing when the countdown [3] is displayed, as mentioned in the other thread. I suggest that the timer start timing as -1.xx seconds from the frame when the first countdown [3] is displayed. it seems 1.00~1.20, but I don't know precise one.

【Timer Stop】 Which is correct in the following three? ・When the pop-up appears at the bottom of the screen even only upside edge. ・When the pop-up appears at the center of the screen. ・When the pop-up appears at the center of the screen and any button color turned into blue(selectable state).

Are Modifiers (ex. Unlimited Multi Jumps, Fastest Move Speed) allowed? Using them can save much time, so I think it should be explicitly prohibited by the rules or divided into different subcategories.

50% category rule descriptions are completely same as portalless, nothing is written about 50%.

How many levels should I clear?

I can see from other people's videos that I must clear 5 levels in Original Levels, but how many levels in All Levels? 50% of 17 levels is 8.5 levels. Round up to 9 levels?