It's de facto a pay to play game (you need to buy "Prime Status" to play main game mode since it went free to play), monetization is fair gameplay-wise, only cosmetics.
Nice game! Consider using key codes instead of characters, right now to use WASD controls you have to switch language (to English or something else that uses latin alphabet I guess).
If extension requires new permission it wouldn't automatically update anymore until you allow it. It's enough friction for such an extension I guess, personally installed it for countless of people and most of them would just ignore updating it.
“We really wanted to accurately represent what someone would see from the ground where they were standing, we didn’t want to misrepresent what would be in the sky above you.” -- strange that shots with trailing stars are allowed in this case, you don't see them with a naked eye.
I wonder why his game has no Steam trading cards, seems like a comparatively easy thing to add to boost sales a little bit and generate some money from Steam market transactions.