The game definitely needs a crosshair or something, its pretty much a necessity for any game that has a gun in it.
I don't understand the endless runner style level being in a 3rd person action game as it just feels out of place and breaks the immersion, the whole time I was wondering why I went from a free moving 3rd person tutorial to this style and which of the two is actually the game I'm going to be playing. It also takes away time that your users could be spending seeing the real open area level that you designed as people won't stick around on your game for very long in a jam, 15 minutes is optimistic unless its very well made or really unique. Also if you are going to make an endless runner style map, create a collider that only the player interacts with to keep them inside the area, don't kill them because they got too close to the edge.
The player models arms are way too long, he can touch his toes with a straight back haha
I liked some of the particle effects you made and the aesthetics of the tutorial level actually had a good atmosphere, a couple of bits looked out of place but it was good overall and the music you selected fit the levels.