None. You can’t stretch the screen to reveal objects that are out of bounds. It counts as screen manipulation.
iirc, suicide clip is a clip you can do in the second running training to get slightly out of bounds and get infinite points. However, (still iirc) it's impossible to get back in bounds and you are permanently out of bounds. Thus, the name "suicide clip". I'm not really the person to ask if you want to know how to do it, but I hope that explanation was suffice to answer your question. As to your second question, there are 2 versions that you can play this game on:
- Flash Version. The Flash Version is used for all the categories except for "In Browser". While flash was axed from websites at the end of 2020, this game is still available via the download in the resources tab. There is also a version which is considered flash on Wix Games. Here's the link if you are interested: https://games.wixgames.co.uk/game.php?id=ducklife4
- Unity/ In Browser Version. This version is now what is supported by most host websites including Coolmath, Math Playground, and others.
Finally, just to relate the two questions, suicide clip is only possible in the Flash Version. While I'm not too familiar with what categories use suicide clip, you cannot suicide clip in the Unity Version. This means you have to download the game from the resources tab, or play on Wix games to play that category.
NMG Any% requires you to have the King of Ducks role to beat the game, since you can’t beat the Champ without having the stats required to earn the role. Having a category like “NMG King of Ducks” would be unnecessary because of this.
Like Caarda said before, under the resources tab is a downloadable file named "Download Version" that is used to play the old (original) version of Duck Life. This is what the "No Major Glitches" and "Glitched" categories use, while the "In Browser" categories use the Unity version, which is what websites such as Coolmath support now. So to answer your question, the world record is beatable since we can still play the original flash version via download.
I’m positive your run was rejected for screen manipulation.
Screen manipulation includes anything that stretches the screen to reveal things that are not supposed to be seen. You are playing the game in full screen, so things that are out of bounds are seen, which is not allowed. If you do not play the game In full screen, then the run should be valid. (I didn’t watch the full run so I don’t know if there are any other problems.)
Go for it. I feel that the route is pretty optimized so are-routing would be tough. Glitch hunting may be the only way to make big time saves.