5/5 on everything! Absolute gem of a game! This for sure will be a big hit on Steam, if you end up making it longer and adding a lot more levels and keep continuing with the story. It was a lovely story tied up to a great gameplay. I liked the fact that you could move them either together or separately, so good!
I loved the small little thing you did in the start if the player tried to go to the wrong direction :D I don't know where it originally came from, but nowadays I almost always try to go and see if there is anything there, you had thought about that and perfectly guided the player to the right direction with some witty dialogue! :)
2 Players could have been really fun, but at the same time I think two players could have made it too easy, not sure about that but I think for it to be 2 players, the levels would need to very hard, and it's always a disadvantage for the second player to play upside down :D
One BIG plus was checkpoints, I didn't realise you die if you get too separated, but I only did it once quite far into the game already, and honestly if it would have started from beginning I would have quit it :D That little factor made my day and I decided I will finish this game no matter how long it takes and it was really good size for a gameJam, but please don't stop the development. You have a proper game here, I would recommend doing some devlog/youtube style job on it or something to get the right audience hooked on it and to know about it and from there release it on Steam and hopefully start raking the money in! Would be VERY good on consoles as well, so that on top of the Steam would for sure be!!
Especially the fact that you guys/gals have done all the art and everything, so well done indeed! I think I have only found handful of games I've given 5/5 on everything but this one for sure is one of them!