I played a couple of rounds against the bots. UT2015 feels very responsive and despite the nice graphics seems pretty well optimized for a game in alpha.
The double tap dodging is back, plus you can now wallrun and slide as well.
The Enforcer does not feel as responsive as I would like, it also has lower rate of fire. I still think that the Enforcer in UT99 felt the most tactile and it got progressively worse over the years.
The Link Gun can now grab and pull enemies and allies.
The Biorifle now has a third firing mode where if you hold both the mouse buttons, the slime slides across the floor.
No changes to the functionality of the Impact hammer, Translocator, Shock rifle, Rocket launcher, Flak Cannon, Stringer minigun and Sniper rifle. However, these have newer models.