Just started – newbie questions

Hi, I just started playing yesterday and have some questions: (where relevant: playing on Android 5.0.2)1. I often get a link "watch a movie" to gain some bonus (double resources), but these always result in a crash. Other movies ingame work, but never the ones that result in a bonus. Any idea what's wrong?2. Is my progress synced/stored somewhere if I use Google Play? Or only local on my phone? Can I somehow switch playing on my tablet and my phone? Just like in AB Epic this is possible.3. I can't seem to destroy the gold blocks. Am I not powerful enough?4. Can I switch/choose which transformer I want to play a level with?5. What's the best way to spend gems (in this phase, max lvl 4 transformers)? I haven't spend anything since the gems seem to be the premium currency and I don't know how many I'll really need later.6. Is it easy to gain gems later?7. Are the accessories really useless? They seem so expensive for just a vanity item..8. I checked the ingame story, when I try to click to buy an item (just checking) I always get "no internet connection available". I really an on WiFi and it's working..Furthermore, do you have any specific tips for starters?