Is there a way to make the fallen (missed) and visible arrows (that the player can pick up) to have a smaller memory footprint, so that the game does not slow to a crawl and crash, after so many arrows are fired and fallen to the ground?
, yes but be sure that the action of arrow is not running anymore (break; in the loop) cause you can have a max 1000 functions running at the same time iirc.
With how many arrows does the project get really slow?
Fps wise: make sure the arrow does not have to many polygons, low textures and disable its shadow if using a heavy shadow system like stencil_shadows(!). Also in many games arrows and such are removed after some time, you could add that too (like after 1-2 minutes). Another thing which is connected to the max 1000 functions, iirc many functions running can also slow down the game.
