Question

What are factors that affect the acceleration due to gravity in projectile motion?
I have a project about angry birds and but I can't find the exact acceleration due to gravity in angry birds world. I experimented, and it keeps on changing.
I m wondering whether the horizontal range is affecting it.

Also, air resistance is negligible.
Thank you in advance!!

PS: if you know how to find the acceleration due to gravity, pls help me!