When you extract the game, the files scatter everywhere, it would be better for the files to be inside of a folder.
I like the artstyle, the options in the menu should have some visual effect, like hovering when you point them with the mouse, or change color or transparency, the music is good and i didn't find any bugs, also a pause menu would be needed.
If you go below a block and hold jump you will do a weird jump dance.
I liked the writing, i guess the only thing i didn't understand is "not being true to yourself" and "hardly the person you should be", i mean, i can only speculate, but maybe adding some power the old self has that the present one doesn't would help.
I think collectables for this game based on the world/time you are would be nice.
Anyway, this was a great job for a first released game jam, i'm looking forward to see what you do in the future!