I love logic puzzles, so this was really fun for me! They're quite challenging. One thing that confuses me is how level 3 and 4 have the same 'I'm not saying anything' guy but one was lying and one wasn't. I don't understand how that happens.
Also in level 8, is having C and E as the only truth tellers not a valid solution? I found your intended solution, but I think there's multiple correct solutions there. Also, as more people were added, I found myself thinking like 'okay, so thiiis guy is E, thiiis guy is G...' and it got a little confusing, It'd be nice if there was more clarity on who was who, like simply showing their letter by them or something.
Anyway, I thought this was great. If you've never played Blue Prince, I highly recommend it. There's a room in the game (parlor room) with a similar puzzle and like 100+ versions of it and those are really good too.