Awesome! I like the idea of the upgrades being tied to the difficulty level.
Do you have a link to the video?
yes! it's from bilibili, a china video share website. here is the link, I'm not sure whether you can click it. I copied the link and it showed in Chinese. Maybe try to click it: 【小游戏】用最简单的画面做出了最强游戏性？！极简风格塔防类幸存者《唯一的塔（The Only Tower）》游玩解说流程_哔哩哔哩bilibili
The player didn't comment on the game but only tried to play his best. The comment below the video are discussing the game design and mechanisms.
He cites your link on the bottom of the description of the video.