You just gotta keep buying those 35K packs and wait. For some reason, it took me a very, very long time to get all of the zombie alternate abilities. I had all the legendary characters long before having all the abilities.
I just moments ago received the ROCKET LEAP ability in the limited time only SOLDIER BRAINZ PACK for 60,000 coins.
It took a while but I learned today it is possible to get with enough time through purchasing enough packs.
Now I am very happy.
Thank you
Enjoy! It's one of the few really great alternates, pretty much a must have for soldier with the way the maps are designed. I only ever change back to rocket jump on the first base of seeds of time to get up over the teleporter on the left.
