Build 14 Alpha 6 is called so because it's an Alpha version. Usually when making a game you will first make an Alpha version where you just stick everything in. Then at some point you'd stop adding new content and start working on fixing the bugs and improving game balancing. This is called Beta stage. Then once you have a properly stable beta, you'd release it. Then you might release updates after the release as some previously unfixed bugs come to light. New updates might also contain new content, new features and sometimes also new bugs. This is the same with our modpack. I think we can consider ourselves lucky that Build 14 Alpha 6 already is as playable as it is, especially with Build 14 Alpha 6 Update 2 installed on top.
We cannot fix that "run as administrator" problem you had, because Alpha 6 is just an ordinary ZIP file. Nothing special about that. Most likely the problem is that the game is in your Program Files folder and Windows is picky about letting anything or anything make any modifications in Program Files. Especially with Windows Vista. Especially with User Account Control enabled. Really I recommend you to turn that off as soon as you can.
The original game did not have sidestep. It was added in as an ordinary horizontal teleport. Not perfect, but it works. Originally (Build 12.1) it was even more jarring, because rather than sliding, you'd just suddenly stand a yard to the side of where you were before. Very weird. There is no collision detection, though plenty of attempts have been done to add that. The most recent attempt by Maximus that is in my current game version seems to be the best so far in that it actually seems to be doing <i>something</i>, which is a first. It doesn't actually work very well though.
We cannot make new animations, so we can't add a sidestep animation. However, if you play as one of the added AoP characters such as Blaze and Beatrice Devlin, you'll find that they do show a proper animation. You can still step through walls though.
WIP means Work In Progress. So Build 14 Alpha 8 WIP 1 means that it is an Alpha version that is still so much unfinished we don't even dare call it a proper Alpha. Meaning it contains a lot of nice stuff and a lot of nasty bugs that we don't want people to really play with. Meant for development purposes ONLY.