Moreso THANK YOU for now two amazing experiences with as best of preservation of the original feel as possible.
I have looked for other games like these online in the past -- never have I found anything (including one that costed $1.99 and totally sucked due to being highly incomplete in my opinion) like these. I am actually doing a runthrough of Infested now. That one will always ring home to me and I think will always be my true favorite because it is the first game of true quality I had ever found that put so much effort into preserving the true "MacVenture/ICOM adventure" feel. I showed one of my closest family members that day and they were as shocked as I was. We both ended up playing and completing both it and Spectacle and he even asked me if I heard anything about the 3rd game the other day :). I am super excited to say the least and looking forward to whenever it comes out :)
Spectacle's conclusion was TRICKY indeed and made you think, but, there is not a single aspect of it that one couldn't figure out with some critical analysis and that was a really good time figuring that out.
Truthfully the only overly odd puzzle to me was the one to complete to cross the desert for the first time. It seems the indication was to speak a certain dialogue based on as written. If interpreted that way and you reach the desert, nothing happens. In these cases, maybe a little hint you're using an item incorrectly or something would have been a little clearer is all. Suggestion only -- doesn't change a single iota of fantasticness of this game!
The story behind the creation of Spectacle is pretty awesome - it's interesting where inspiration can come from sometimes :). I think the tie-ins of the circus and other world worked perfectly and made for a much more expansive and intriguing game for sure.
Admittedly, I did miss one thing and had been wondering. I did recall this game was an unofficial prequel to Uninvited, but I think I missed some of the connections. I got the gem, the creature and an ending gesture (nice touch and references). The one thing I didn't understand was the location tie-in. Are you saying the circus itself is actually supposed to be located in Scotland?
/edit - final thought - you should charge a couple bucks for your 3rd game honestly. The quality you and team deliver has been proven and I'd gladly pay a small entry fee for the 3rd installment :)