For a first game (or one of your first few projects) this is alright, although quite simple.
Some criticism/feedback:
-You really should include a HUD, the player has no idea how much HP they have left.
-If you run ahead of the camera, the game will kill you.
-Likewise, in vertical scrolling sections if you jump while near the top of the screen, the game will kill you.
Viewing post in Four Ninjas jam comments
No problem! There was also one more bug I needed to mention to you.
On the vertical scrolling stages, if I paused the game, the screen would continue to scroll upwards.
If the character was off the screen by the time I unpaused, the game would kill me.
Since your game is designed around keeping multiple players on the screen as it auto-scrolls, you'll probably want to make use of the object parameter/setting to bound them to the game screen. This makes it work like auto scrolling stages in Super Mario 3, or any top down shmup, etc. where you cannot move off of the screen and are forced to move along with it.
The way to handle killing your player if they were to be crushed by a solid tile and the edge of the screen is to have their death sequence also trigger if the object gets stuck within a wall (it's one of the link conditions you can make use of). I think this would be a definite improvement to your game.