Some apps check their app bundle identifier (Bundle ID) to prevent sideloading/cheating.. many online/offline app signers choose to add a random prefix or suffix to the app Bundle ID "to avoid Apple flagging the account" for sideloading an AppStore app. Too many sideloads of AppStore apps will result in temporary suspension or revoke of that developer certificate. This "feature" is sometimes called PPQCheck Protection. If you're able to change the Bundle ID, copy and paste the original Bundle ID of the app, it will bypass the protection, but it will also increase the chance of the cert being revoked.
Some games further require the app to be signed with Explicit Ad Hoc Provisioning + Distribution certificate, rather than the usual Wildcard certificate. This is especially so for apps which attempt to connect to AppStore to validate the app, sign in to your Apple ID/Gamecentre, or check previously purchased resources from AppStore. If your signing method doesn't have this option, then it will just say "Loading..." and then eventually fail with a "No network connection" (to AppStore).