Game is great but some parts are kinda drawn out, like Dilation or Cel5. The rest is fun, especially early Eternity and the Reality stage and the final sequence is satisfying.

I saw your run and it seems it was rejected because of Speedrun mode.

Speedrun mode starts off with extra achievements (time consuming ones like the 6 hours offline achievement) and thus makes it easier due to achievement multipliers. This category focuses on restarting the game from a new save (pressing RESET SAVE button and entering the confirmation).

Although, if you want to use Speedrun mode or just speedrunning the game in general, you can join the official Antimatter Dimensions Discord server and using the #metagame-and-speedrunning channel (it is also a cool place to hangout or talk about the game in general and I really recommend joining).

Hope this helps you! (Also sorry for any mistakes as English is not my primary language)