Well regarding speed, I think a faster speed might be good, not necessarily the fastest you can go, either that or the time it takes to speed up to full is lessened. Running that slow at the start is really boring. As regards the lane changing, jumping and sliding quests, this can be done very very easily at the start as @80 suggests, so they're not really challenging.
I've noticed the swipe lag too and I don't know what that's all about, it's not horrendous, it's just there. It has killed me, but more of what kills me in regards to what I would call touch screen errors are swipes just plain not working at all. Like no sound, no movement, it's almost as if I didn't even swipe when I did. I've experienced this with lane changing, jumping, and sliding.
The weapon I honestly don't use because it's a good way to die foolishly. You go chasing zombies and it doesn't work, which I've honestly seen happen, or it gets to you before the weapon works, or you misjudge the time it takes for them to get to you and you die. If a zombie is in the same lane as me, I'll shoot it, else, I don't bother because I've died more trying to shoot them than I have if I just leave well enough alone. Also I'm not quite sure of shooting them gives a bonus. If so, I'd probably be willing to risk it more often, if not, its not really worth it.
I would estimate my deaths caused by game issues are probably a bit more than a third of my total deaths. It honestly happens a lot for me. I'm pretty good to go, and while I'm not great by any stretch, I can usually survive a box in attempt or something. But when I die of hands or ravens at moderate speed or something like that because I swiped up and my char did not jump or swipe down and he didn't slide, yeah its a bit annoying. The times when I feel the lane changing swipe issues happen worst are when you're moving fast, because you usually don't get another chance. I've taken to repeating the swipe up and down gestures multiple times in quick succession to make sure it works. I can't always do that with lane changing since I might walk into another one while trying to avoid his brother on the left.
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