It's too long for a comment, so let me drop it in here:

Case 1:
1. Make a portal like this: https://steamhost.cn/steamcommunity_com/sharedfiles/filedetails/?id=1619949984 - the best way to do that is to stand almost at the ledge.
2. Descend above it: https://steamhost.cn/steamcommunity_com/sharedfiles/filedetails/?id=1619950010
3. Switch the tunel to exit from the newly created white wall and descend onto it: https://steamhost.cn/steamcommunity_com/sharedfiles/filedetails/?id=1619950010
4. ??? https://steamhost.cn/steamcommunity_com/sharedfiles/filedetails/?id=1619949505
5. PROFIT! https://steamhost.cn/steamcommunity_com/sharedfiles/filedetails/?id=1619949594
6. also if you jump from here: https://steamhost.cn/steamcommunity_com/sharedfiles/filedetails/?id=1619949624
7. You will survive a drop to the very bottom! https://steamhost.cn/steamcommunity_com/sharedfiles/filedetails/?id=1619949666

Case 2:
1. Catch a lot of gel: https://steamhost.cn/steamcommunity_com/sharedfiles/filedetails/?id=1619955613
2. Switch the exit of the tunnel to that white panel directly in front of the hatch: https://steamhost.cn/steamcommunity_com/sharedfiles/filedetails/?id=1619955694 - almost all of the gel will fall down, except for one drop that will happily travel through the hatch
3. Remove the tunnel once the blob is above the platform behind the hatch. Congratulations, now you can shoot a portal there! https://steamhost.cn/steamcommunity_com/sharedfiles/filedetails/?id=1619955931
4. ???
5. PROFIT! https://steamhost.cn/steamcommunity_com/sharedfiles/filedetails/?id=1619955438

To be honest I have no ♥♥♥♥♥♥♥ idea how you could even patch it, so maybe it would be better to add easter eggs there or whatever. Anyway, good luck and thanks again for the map!