I've test some maps with this glitch and it's works. Only with a death by a living being (Sligs, Scrabs, ...). Just have to reset before the spawn of birds, <0.5 sec approximately.

I've got it on video: I don't think the link with the gateway was obligatory.

Ok, i'll try to make this on video :)

Hey everyone, I've find a bug, don't know if works everywhere or already find, in Monsaic. I tried to restart chapter when I died with first sligs. The restart works but I still on checkpoint with sligs. The result was the IGT reset on the checkpoint. That why my IGT on Monsaic was 3:01 but the RTA counts the beginning of level (3:50). Good IGT but bad RTA. Should we work on this glitch or forget it?