There are a few possible reasons why the game will not open. We recommend to not immediately uninstall the game- sometimes there are other approaches that will fix the issue. Uninstalling the game will lose saved games and stats, and sometimes your gigawatts.
First- try deleting your iCloud data. Go to the Settings app->iCloud->Storage and Backup->Manage Storage->Show All and tap WELDER, then delete the data. This will not delete the app, but instead will delete potentially corrupted iCloud data.
Second- Check the app update information on the WELDER updates page in the App Store. If we were to find a crashing on launch bug for a particular subset of users, we will post that information in the update notice so you do not download the update. If you already did (obviously, because you're reading this), then know we are actively working on a fix and to please contact us.
Third- power cycle your device, quit background applications, and/or try launching in airplane mode.
Lastly, none of these solve the issue and you have contacted us, sometimes deleting the app and resintalling will fix the issue.
To contact us, click the "Submit A Request" link in the upper right corner of this page.