1. it's not "new" or "innovative"
2. let's be honest, no one's gonna play it longer than 3 minutes
It's possible to take an existing idea and give it a unique spin. A lot of games today are just recycling old concepts but in new ways, so don't let it dissuade you. You'd be surprised; there's still jam games from years ago that I come back to today. One of the neat things about being able to build games is you can build the ones you want to play. There's no prizes, so don't think too much about what people might want - just build something you want to play (while avoiding copyright infringement obviously).
Can my entry be a remake or a demake of an existing game?
No, games must be original and not use existing intellectual property.
it can’t be a Pokemon game. besides copyright infringement reasons, fan games or demakes are not allowed. so you can’t use existing characters from other intectual properties. but there’s nothing stopping you from stealing mechanics from Pokemon or other games.