For the first question I really have no answer. Something similar happened with me, but it affected HL1's res. It may as well be a compatibility issue.
As for the second one, the things that are still broken are:
- The water reflections. They don't really work well and like to glitch out.
- The game will crash during a level transition if you've been caught by a Barnacle.
- The game will sometimes crash during a level transition if you saved your game on a map with physic props.
- The game will sometimes crash during a level transition because it can.
- The laser-sight on the Rocket Launcher will sometimes not work and you won't be able to steer your rockets.
- Shooting moving striders [On maps like e3_c17_02 or e3_strider] will make them stop in their track.
- Scripted sequences can be janky as hell but that's really a problem with the overall beta itself just being, well... a beta.
All of these are fixable, but it will take time before that's done. VXP [The guy who made the Leaknet patch included with the Mega Build] still has a life to take care of.