First of all you need to bypass hackshield here.
DOWNLOADS : The Carat and EXP hack
CheatEngine 5.5 (So it doesn't leave a trace)
1. Open up Cheatengine!
2. Run rumblefighter (I suggest in windowed mode)
3. Attach Cheatengine to Rumblefighter [process name is RfNoHs.exe]
4. Tick the speedhack to 500
5. Open DevilTweet trainer And ignore the EU unless ur in EU XD
6. Tick on the Carat hack
7. Run Zombie several times~!
*OPTIONAL*
Open another DevilTweet Trainer and tick exp hack, sometimes it's glitchy and if it shows ur lvl 98, restart rf
+Rep Me please =3