Some answers:

Controls: I've heard this suggestion several timesalready, but the bottleneck is the keyboard. When having movement relative to the camera you will end up pressing at least two keys at the same time - which makes it impossible to play for two players on just one keyboard in most cases. With the current controls you can at least take care that you don't press too many keys.
I'm not sure whether I'll still touch this, as it has major impact, also on the AI behaviour (time for turning into an direction can be different and such things). Plus it kills the fun when the camera is rotated and everybody who isn't used to it gets confused

Camera: The problem described often happens when a speed extra is collected. This was intended as aou're not supposed to have perfect control over your character in speed mode. Sometimes this problem happens in slowmotion mode as well, because I'm changing the arc, I'll hav e to think a bit more about it.
I've had this problem with the camera jerks when teleporting. This is why I limited the z height (maybe the limit needs to be set lower). It should not snap forth and back, though. Strange.
There is a chance I forgot to set fps_max to 100 in the demo. This can cause such issues... I'll check this later.

Network: The game had A4 network support, which was rewritten since then (A4 networking was a bit buggy). I had to drop support for it. Re-implementing network would be hell a lot of work maybe even impossible with the current code layout, so unfortunately I have to answer this with: Sorry, no network/online gaming.

A6 port: This game will be finished with A5. It's more work than advantage porting this game. My next project will use A6 and at least some shaders - promise

Player menu:
When playing alone(!) a single stroke on the fire button and then enter key when done is sufficient. However I'll probably add a "press fire button when ready" message because this is not clear. This second confirmation is required so the game cannot be started once everybody has set up his player. In the demo there is not much to select here, the final version will allow different warriors to select from. This is a just for fun feature, they all have the same abilities.

Armor/Health:
There is no armor and no health. It's all about crystals.
You cannot run out of energy permanently.
The two bars are stamina and ammo.
Stamina automatically recovers. The more stamina you have, the more damage you'll do on a golem and the more crystals you can steal from other players. Wehen blocking, stamina is drained, maximum stamina (when the yellow/orange particle appears and a short sound appears) allows to do special attacks.
All you need to do is to get as many crystals as possible by collecting them, slaying golems, attacking other players, or using special items out of boxes.




One more thing:
I know the gameplay is strange, and I know you don't understand much the first time you play. It takes some time to get used to it. So everybody who did not uninstall the game after only a short try: Thank you for actually trying