Hi!! Thank you very much for your feedback. I watched your video and it was really helpful feedback to us! We're very glad you took the time to play and enjoyed it!!!
[Spoilers Below]
There are 2 parameters the game uses to determine your ending:
If you completed Mary and Renko's Journey by the time you reach the graveyard-looking car, then you will be able to see a cutscene where they leave. This will determine if you can get end 1 or 3, and if you do not complete this then you will get end 2 or 4.
The game also awards points towards Renko or Yuyuko depending on certain actions and dialogue, this will determine wether you get a Renko (1&2) or Yuyuko (3&4) end. Unfortunately this is less easy to control as the points are pretty randomized (There was supposed to be tied to mroe obvious dialogue choices). Where you sit with Yuyuko in the beginning will award points (If you sit together in the Love Seat), and also theres an optional cutcsene in the conductor's car that will award LOT of points to Yuyuko which is the best way to guarantee you get one of her ends. Unfortunately there's not really an easy way to get Renko's Ends. I think if you keep using the wrong spell card on the Gravestone then you can farm for it. The game was supposed to be bigger and more concise, but de-bugging took longer than expected, so some things had to be cut. There was supposed to be different ways to open the doors. This (And the Jam time limit) is part of why some tiles can be re-activated - so that people can gain Boundary Break Points or Renko/Yuyuko Points in the matter that they couldn't gain them. Especially since the one after that car doesn't give many opportunities for a boundary break despite it being your last chance to complete the Renko and Maribel route, because of timing we weren't able to add much to that car >.<.