Customers of Google Play are very fortunate with refund windows for apps and games. Google has long had a refund window implemented with the time limit being fifteen minutes. For some downloads, that amount of time is just not enough. So Google has extended the refund window for apps and games in Google Play to two hours.
The change is now official as the Google Play Help page includes a description of the new policy. Within two hours of purchasing the item, Open and Refund buttons will be found on its page. This leaves when the time has passed and Google recommends contacting the developer to try and get a refund if unsatisfied.
Source: Google Play Help