Hello takeobass, welcome to EAB
I just tried the original Alien Breed and I used a standard A500 quickstart config (512K Chip RAM + 512K Slow RAM, KS 1.3) and it works fine. However I got an instant software failure on a KS2 setup, but stick to 1.3 and it should work.
(I used the ADFs linked to in
this thread.)