Not just solid, adamantium reinforced with granite, laced with anti-magic runes and defense enchanted solid, with an energy barrier around it that can take power equal to several hundred nukes solid.
Gameplay is simple, which is rather good actually. It makes it rather easy to get into play, after you pass the introductions, especially the tutorials. I'd say the dialogue box interface could be improved. Whenever I want to skip and fill up the box to just read outright, there's simply too much and it causes it to go into scroll.
At first, it's annoying, but takes time getting used to. Another gripe is the staircase. Not all that major, but at the start it can affect how we enjoy the game. Going up and down stairs are generally uneventful, I personally recommend just skipping the entire go-up-and-down stairs sequence, and just go straight to the next floor or the floor below once you reach the stairs. Of course, also took time getting used to, but since nothing happens in-between going up and down stairs, it is just generally pointless.
The writing is, perhaps some of the best I've seen. There is a brand of black humor about school in this entire flash, and it is rather involving, considering we've all been in school in our lives, so it is sometimes relateable. The addition of humor, and that this is an entire cast of snowflakes makes it even better. The fact that there is a profile on every student, with all of them having something different to each other, really took the cake. I can't say too much about the plot, I've yet to see it all, but I hope the rest of this series does not disappoint.
Overall, really good. The fact that I sat here for hours just playing proves it's good. And to those poor, impatient and generally incompetent sods who can't get past the starting pace being slow. You guys are really missing out. There is just simply, so much depth in this one flash game, it's incredible.