No it is not necessary at all even if you don't kill the enemy but reach the finish line you will win the game
Viewing post in Oppenor jam comments
1 thing you could have done that'd make the game more interesting, would be to allow players to get back towards left from right, even though that is not posible with the current level design, I think you could have implemented a sort of cliping glitch that allowed the player to get back and end the level.