jsut checked back after the last upgrades, nothing changed in regards to last level, guy is still a filthy liar. (literally used his "this is the perfect setup that the developer intended" placement)
WITH mouse, it can just barely not beat the level (boss always has more or less very little health left at the end),
let alone some "oh I didnt even sue my mouse. I just placed my towers and went wanging off and when I came back i had already won. Also everybody clapped." nonsense -.-
I can't tell if you're trolling or not, but in case this is earnest, I just beat the boss like this. Apparently my placement is similar to most other folks, probably by design. (The cursor completely doesn't work on Chrome on a Mac.) I guess it's possible there's a bug, but just echoing that it works for me.