Hey all! So, I'm wondering if I use DataStore to save an amount of kills, or any numerical number, would users be able to use Cheat Engine to change the value of the DataStore?
DataStore saves data, that's it. There's no exploitation preventation tied to DataStores other than you not being able to change stored data. If you really want to go about preventing exploitation look into FilteringEnabled.
What FilteringEnabled does;
FilteringEnabled, or FE, makes it so Client to Server communication is inoperable without taking advantage of RemoteEvents / RemoteFunctions. You can read a full tutorial on those here.