Well, according to what you said (I didn't tried the game), this game could be server sided:
- values remain the same after modification --> may proove that the server is verifying some data and blocking their edition. Yes, solo games can also be server sided.
- A cloud has nothing to do with server sided games. A cloud is only a server where you can save your data, and it's not always for games (dropbox is a free cloud you can find on internet for example, to save any stuff on it). Some games may have a cloud without being server sided; for example, grow castle: you can easily cheat the game (not server sided), and you can save your progress, cheated or not, on the game server (= cloud). In your case, brutal street 2, in my opinion, may be server sided, but like the devs said, it hasn't a cloud to save your progress and recover it. That's why you can't restore your progress after uninstalling the game without manually saving it. I hope i was clear : cloud ≠ server sided