Sooo... I figured out how to add rollback and skipping, it's actually easy:
Inside the "game" directory there is the "options.rpy" file. Open it with Notepadd++ (or another program for editing/programming/etc.) there are lines of codes for rollback at line 109 and skipping from line 167 to 172.
For rollback you just have to change "False" to "True".
For skipping, what the code is doing is to remove the keybindings related to skipping. I don't know how to actually change (e.g. add more lines) the code (else there is an error output), but you can go around it. You can change the ".remove(" part to ".append(" so it adds that keybinding instead.
Example:
config.keymap['skip'].remove('K_RCTRL')
config.keymap['skip'].append('K_RCTRL')
This makes it so right control gets removed and added again, left control doesn't get removed now, so both work again.
Edit: Ignore what I just wrote about enabling skipping, it is there for a reason (or else the game breaks).
The problem is that there are situations where skipping must be disabled, for example while roaming around, or else the game tries to "skip" that part, but somehow ends in a loop with the potion in the box from the beginning of the game (it isn't skipping "linear" parts like it is in other renpy games, it skips through some vital parts, which actually isn't "skipping" but rather "glitching").
Edit: I am bad with theories, but at the end it is breaking the game.