Hey, the problem is that due to the size of the game, it is not possible to build a normal apk, which is why you need the launcher. Which file is it crashing on? It could be a server issue.
Changes have been made for that, a fix has been uploaded for gifts, but previously they were limited by days; in the next update, they will no longer be limited.
Everything is working correctly, it has been tested several times, the servers were down due to a problem, but now it should be working. If not, please download the update again.
Hey, it's not a problem of the host, the launcher is the only way to get the apk version working at the moment. If used correctly, it shouldn't cause any problems, unless there are server-side errors, which cannot be predicted and are handled by external people.
There have been reported and fixed for the next build, we forgot to change the name during that part of the game, after that it is fixed automatically.
The BGs for the girls' card are unlocked or by progression of their story or by stats, for example Taile Forge bg can be obtained after her event there.