Okay, so, no one said that this simple game was going to be a rollercoaster of emotions. Even in a first playthrough, it feels too much of a joke to be taken seriously, and then you do everything you think the game has to offer at first and close the game and realize you've got some more exploring to do...
BitBuddy has the obvious Tamagotchi feel, allowing you to take care of your reluctant friend, all the while being reminded about one very important message: "Don't close the game". At face value, it really does feel like a demo of a game that can be released later on; you do small things like feed your buddy, play an RPG-style game with your buddy, and even take your buddy on vacation! Once all is said and done, all you can do is close the game, right? Well, that's where this game takes a turn.
***SPOILERS UNTIL THE LAST PARAGRAPH***
Upon closing the game at any point in time, you will be greeted to your Buddy having decomposed into a skeleton (presumably because the game was "programmed" to end the Buddy on close since it's a demo). While this is grim since your Buddy hinted at this multiple times during the game, the game grows a feeling of melancholy if you decide to stay with your Buddy after "completing" the demo. As the hours progress, your Buddy will recount the time they spent with you as they age quickly over the hours. They'll remember the games you played with them, and wish to relive going on vacation one more time. If you make it to the max time limit, you will reach the ending of your Buddy's life as they tell you how much you meant to them before passing away.
While I didn't take the time to attempt playing through the RPG portion of them and get as far as possible, there weren't any glitches that I could find during the mini-games or attempting to do things out of order (I did crash the game with non-stop food at one point though). The time you have to wait in-game to get the true ending is extremely long, but not really a point of gripe as it's supposed to make the Buddy more endearing and add value to having spent all that time with them.
***SPOILERS OVER***
All in all, what seemed to be a slightly funny premise turned into a rollercoaster of emotions where you learn to value life (or not, it is just a virtual Buddy after all).
My playthrough: