You won a giveaway for "Tumblestone" in November 2019:
https://www.steamgifts.com/giveaway/OKeBv/tumblestone/winners

You marked it received, however I would like to ask you to check if this is the full version or trial version of the game.

It is still called "Tumblestone" in your Steam library, but if you have the trial, when you start the game it will say on the title screen "Trial" right under the Tumblestone logo.

If you have a moment, please can you check? I would like to make sure you received the full game as intended. If you have a trial version, you can only play online with friends who invite you, and only as the "grey blob" character. Additionally, the story mode is limited to just 30 sample puzzles, compared to 360 puzzles in the full game.

People with the full version used to have the ability to create trial keys freely, which is why so many giveaways appeared. If you received the trial version only, we can change your feedback to "Not Received". Please let me know. Thank you!

Yeah, it says trial.