The video
@kburkhart84 mentions from
@matharoo is this one, and it's well worth watching. The subject matter is deceptively simple, but the underlying principles it illustrates are incredibly powerful:
As for things you can use sequences for... here's a brief list of things that immediately come to mind:
Timers: Use sprite masking to create cool-down timers like those in RTS games
GUI: Buttons and general interface elements (the broadcast message stuff is great for this)
Logos: Create animated intro logos and gameplay elements like Game Over, etc...
Gameplay: Make your player character use sequences for each different gameplay animation, running, fighting, etc... and use broadcast messages to trigger SFX at the appropriate times
Backgrounds: Use a sequence to create an animated background to your levels
There are surely an infinite number of things that sequences can be used for, and I'm sure that people will be discovering and posting about them over the course of time, especially when 2.3 goes stable. Personally I'm incredibly excited to see what people do with them, as it's such a deep tool that I'm sure there are many, many things that even the Devs haven't thought of that people will do. Not to mention the fact that with any tool like this people always find little "hacks" and workarounds to stuff that it was never intended to do!!!