Drag left or right to aim the falling cube, then let go to drop it. Land it cleanly in an empty spot to fill it. Cubide is the opposite of a stacking game - you're filling lines, not clearing them.
If your cube clips a cell that's already filled, both cubes explode and the spot reopens - no game over, just a small penalty. If you miss the whole play area completely (the void), that's game over.
Chain successful drops without a single mistake: 7 in a row earns a Bonus, 10 earns a Bonus+, 14 earns a Mega Bonus. Each one auto-fills one or more empty cells for you - use them whenever you like, they carry over between stages.
Every successful fill earns points, with a speed bonus for quick decisions and a streak multiplier that grows the longer you go without a mistake. A mistake resets the multiplier and slows its regrowth for a few drops.
Players are ranked by the highest stage reached first, then by score, then by whoever got there first in case of an exact tie.
No - you can play right away as a guest. Guests get an auto-generated name like "Guest_4821", save progress, and appear on the public leaderboard just like signed-in players. Signing in with Google or Apple lets you pick your own name and keeps your progress safe if you ever switch devices (your real name/email is never shown publicly either way).
Yes. Signing in from the same device automatically upgrades your guest data to your new account - same stages, same scores, nothing is lost. You'll just be asked to pick a real username, since "Guest" names are reserved.
Yes, from Settings while playing as a guest - "Delete my guest data" removes your guest scores and progress from that device right away.
Use the Contact page - we read every message.