OK, once again, thanks for the feedback Ath and Jibz, and for your patience waiting for a response! Here are my point-by-point responses:
I've been playing it for half an hour, but I can only conclude that my Samsung Tab2 is too slow for this game. I can't flip the cubes fast enough to finish the levels within the assigned time. I'll try it on my phone (nexus 5) to see if that works better.
-Ath
Do you happen to know the exact model of your Samsung Tab2? The name should start with "espresso." When I look it up I see there are about 10 different variations (most of which are just different carriers, e.g. the Verizon model vs. the AT&T model). Or can you at least tell me if it's the 7" model or the 10" one?
But yeah, games generally do require a bit more of a powerful device. Cubiq doesn't run very well on my phone (Galaxy Nexus from 2011) either, but at this stage of my phone's life, nothing really does.
Doing step two, I get "We're sorry, the requested URL was not found on this server." from Google Play.
-Jibz
I've added a note to the instructions saying that the link might take a few minutes to activate, once you've joined the beta.
My Nexus 5 is running quite hot after 5 mins of play. Would it help to turn off the fancy backgrounds?
-Jibz
Is this not normal for games? My device(s) always heat(s) up when using the GPU.
But we might be able to disable fancy backgrounds and particle effects, which, if it doesn't solve the heat problem may still help with the sluggishness on older/lower-end devices.
A back button on the stage complete screen would be nice.
-Jibz
That's a great idea!
The time and move counters are teensy weensy tiny on a 5" display.
-Jibz
Can you please attach a screenshot? Or tell me the resolution of your 5" display? I guess I've been taking screensize for granted when I test on my 2560x1440 monitor and my 1920x1200 7" tablet. But yeah, I agree that the numbers need to be larger. They used to be, but then we revamped the UI and I guess they got resized.
At level completion, I would prefer a dialog with level complete and a next button instead of the fireworks (5 second waste of time).
-Jibz
I agree the fireworks take too long. I'll see what we can do about making that part more streamlined.
Could it not ask me to create a google play ID every time the game starts?
-Jibz
The game uses Google Play Games Services for achievements. Are you not signing in? Or are you signing in but it's asking you to sign in again anyway?
If you're not signing in, AFAIK, it's considered "best practice" by Google to just try to connect automatically when the app starts. It uses your Google account, which you needed to download the game from Google Play to begin with, so you shouldn't have to create any new accounts or anything.
The stage select left/right scrolling is too fast -- to go one item left or right you can only move your finger a tiny bit.
-Jibz
The scrolling may have to be reworked, but it may help you to know that you can just tap on the cube to the left or the right to move only one space over.