Hi, It's been almost 20 years since I played Pokemon Red,and I want to discover the speedrunning with that. Like many others, I block to capture a perfect nido. At each manipulation, I catch a Nido lvl 4 on the right tile... but it"s a Nido 18/9/8/9/8... I reset the game and restart the same save... to cach the same Nido... Should I start again from the beginning ?

First of all are you running on the right emulator? Some (most) emulators don’t run correctly so make sure you’re using Gambatte with GBC bios.

Assuming you are using the right emulator and that you are doing the manip correctly I have two possibilities that I can think of. It is possible that it’s an IGT0 that’s causing the issue, in which case you should save the game again and then retry. Another possibility is that you have excess sprites loaded. I had that issue while trying to do the easy perfect Nido (the one with only one A press) and it was easily resolved by simply re-entering the mart and resaving. I’m still pretty new to this myself, so there may be others who are more experienced who have other ideas.

Also the RNG manips need to be followed exactly from the videos. You could simply be pressing an A press in the wrong spot which results in the wrong nido or even taking the wrong path. Really hard to know what is wrong without knowing which manip you are doing and having a video to see what you are doing.