[zokemon]

player.level.projectiles[player.level.projectiles.size()]

wouldn't work anyways as that doesn't exist.

An array with a size of 1 is only gonna have index 0, same as an array with size 2 is only gonna have 0 and 1.

You want:
player.level.projectiles[player.level.projectiles.size() - 1]

Though I'm pretty sure almost all TProjectile variables are read-only.