instead of waiting for an answer that wont help you at all, why are you trying by yourself? we cant generalize all the obfuscated games, because all of them are structured differently.
i guess the problem is that you used void, which void is a non-returnable, and istead of just typing "
old_Update(instance, param_2, param_3, param_4);", you have used return too..
it could be signature verification, witch you can kill it with np manager, lucky patcher, mt manager (or mt vip), apk analyser+, or some anti cheats located in the dump.cs
the first one is a normal offset, it can be hooked or patched, but the second one is a field one, and it can be modified with an update offset (that means hooking)