- A Countdown after starting a Quest in order to complete a Quest and get rewards
Yes, keep in mind that you either need a server for this or accept that people will be able to cheat. Shakes and Fidget defenitely also uses a server.
- A ranking for Players
Yes, also needs some sort of server/database
- Animations in fights
- Animated Gifs as a Background
Not sure if this is the best way to do it, but generally that works
If you are new to Construct and/or gamedev in general keep in mind that this isn´t exactly a beginner level task but if you are up for the challenge go for it.