So tonight I finished bags 3 - 5. Well, mostly; I left out the sign bit to do later, and I jumped to the end to build one of the cars (literally the last bits you build for this set.) But in general, the right half of the Roller Coaster is finished.
The build was tedious, to say the least. If I wasn't building more columns (which had enough slight variations that I had to pay attention to each one) then I was building one of the supports. The whole thing is modestly sturdy; I wouldn't bet on any stress tests, but it'll hold it's weight for the most part. The most precarious design is the angled bits on the front (where Batman's standing) which is essentially a base for the tracks being held up by two clipped support beams, which is currently not sturdy at all. (But upon closer inspection I realize the sign bit would lock the bases of the two angled beams, thus creating a full triangle.) So it would probably be sturdier if I accurately followed the instructions. There was a bit of technic building on the top, consisting of the gearbox for the top of the chain and the wheels that pull the cars around the top curve. A few clever designs there, but I'm sure nothing a Technic fan hasn't seen before.
This is about as tall as the structure will get... and it's tall. It's not quite as high as the Ninjago City tower, but it definitely reaches the top of the third level with the sushi table. There weren't any actual new figs built here, but there were a couple of new pieces I found interesting. One was a 2x3 plate with a bar underneath which has shown up in a few sets, but is new this year. It's not exactly versatile, but I'm sure it'll be useful for some designs. More interesting is the 1x2 curved brick which is not only brand new but exclusive to this set at the moment. (Alas, it only contains two.) This element would be extremely useful, although I didn't test how the curve compares to similar bricks. Hopefully it starts making a wider appearance in cheaper sets, but it has a very specific use in the chain gearbox for the Roller Coaster, thus requiring it's creation, because I don't think any other bricks could pull off the same design. Getting to add in some of the track pieces was fun too, and the little car glides easily down them.
Looks like I'm back to building the base tomorrow, but there's the more complicated loading platform to make, as well as a few of the stalls, so hopefully enough to keep me entertained. Although I do get to build the sign; I was saving that for when I'm not burned out; I need a break from building more supports.