Played some of PADW, and while I still don't understand the overarching goal the basic gameplay aspects are more clear.
- stones and friends are shared between games. That's it
- no REM; you either spend 5,000 Tama medals (the equivalent of PAL points) for a bad roll or 50,000 for a rare+
- every board has some fixed goal, like "2+ combo" or "clear 4 dark orbs simultaneously". Your combo doesn't deal damage unless the goal is met
- there are special orbs that can skyfall that have various effects like orb changing, erasing all orbs of a certain color, etc. these are activated by tapping the orb
- your equipment can affect the type and probability of special orbs appearing, I think
- no fusion of any kind; dupes are automatically fed to each other to level them up
- owing to the larger board the goals so far have been pretty simple, but I can see them ramping up in difficulty over time.
- check out my wig
Edit: okay I just came across TAMA VEGAS and I think the gameplay hook is a lot more apparent now. Instead of a lifebar you have a timer that represents the total amount of time you have before you die. This can be filled with RCV orbs or by clearing waves. In TAMA VEGAS you just have the goal of clearing X number of color orbs before time runs out. There's also a combo meter which can be leveled up by clearing orbs. The higher the level, the better the rewards, but your timer drains faster. So the tension comes from trying to level up as high as possible without clearing the stage and without running out of time.