I should probably post a few observations:
1) FPS is indeed capped at 60 (so won't go much higher than 62~64). Additionally, it would be really interesting to see a comparison between what you get inside this demo (without using any speed boosts) and what you get in the old client in Hydlaa at high graphic settings (type /fps ingame to show fps at the top left of your screen). Because basically, if you have 12FPS, that might not seem much, but if you only have 6 in the old client, that would still be an improvement. So far, on a few dev PCs it seems like the fps improves, but well, it would be interesting to see if that holds up to larger ranges of system specs.
2) The landscape was not copied from the old game since it does not have a landscape (all hills around Hydlaa are just textures). As a result, the landscape in this arcade release is not optimal, at a few places it might not line up perfectly with Hydlaa itself, in particular if you go outside the city this will be noticeable. This is being worked on, and will be fixed when the rest of the map is completed (places like the Winch, Arena and Hydlaa East still need to be placed, and until they are, landscaping will have to wait a little).
3) The crystals are spawned in partially random patterns (as far as I remember), so sometimes they might spawn at locations where they cannot be picked up properly (or only at great effort).
Edit: figured I should add some fps as well (note: this system is about 6 years old and wasn't top of the line back then)
UE-Arcade:
40 fps while looking at the windowless tower from behind the plaza fountain (which appears to be the lowest FPS I can get anywhere)
Regular client:
22 fps from the same point, and the tower + some other buildings were not rendered (half of the fountain water wasn't rendered either)
I can get 55~60 fps in most other places using the arcade client. In the regular client I can get about 65 fps when looking at something on the edge of the city, but when I look towards places where there are more buildings (even if obscured by others), I get around 30 FPS.
So while it seems like UE only draws what you can see, the current client draws *everything* in the direction you are looking at, even if you have a blank wall filling your whole screen (this is actually one of the reasons why the arena and hydlaa east are different maps).
In general, for me, the UE arcade demo performs far better in Hydlaa, and I get cool stuff like shadows as a free bonus.
Relevant System Specs:
AMD Phenom II X4 955.
16GB RAM (not really relevant as long as one doesn't run out)
ATI HD 6870 (1GB) vid card
Windows 7
