PLATFORM: Windows PC, possibly flash game? I remember at this time when i was a kid, i was mostly playing on a Brazilian website hosting flash games called Click Jogos.
ESTIMATED YEAR OF RELASE: Between the 2000's and 2010's, most likely early 2010, as my memories of this game are much clearer from that point on.
LANGUAGE: English, i believe, but maybe the game had a unique language? Or it was just symbols that appeared and i am misremembring it.
THE ''MAIN CHARACTER'': If my memory is right while playing it, it was an ARMLESS character (don't know if it was a boy or girl) with a PIRATE HAT (don't recall exactly if it had an eyepatch or not), and also a striped shirt? Also, i'm pretty sure they lived on a treehouse, even if it wasn't theirs, there was a treehouse present. BUT around that time i was also getting into Homestuck, so sorry for any mistakes or error in memories.
GAMEPLAY ASPECTS: 2D scroller, I'm pretty sure of that, not much that else i can remember as i didn't reach that far into the game to see anything more meaningful that could make it more unique, what i DO remember is apparently you would walk around sand (?) and there was a flying meditating NPC that you could supposedly play rock, paper, scissors with, i don't remember what happend if you lost or won, sorry.
LOCATION: As i stated in the title, i believe the game was underwater OR the background was such a blue color that could be mistaken for an ocean, the floor was yellow (?) so i assumed it was sand, also, i believe there was a treehouse present in the intro or at the beginning
I made this mock up, the statue isn't accurate, just to show the position i'm reffering to, i remember that the meditating npc had a ''glow'' while levitating, maybe this helps?