Do better, HBO. This is embarrassing.
There are a lot of great reasons to want to watch a regular TV show in VR. It's great for having some privacy on an airplane or long-distance train ride, more comfortable than holding your phone in front of your face landscape for 20-40 minutes at a time, and generally a fun way to show someone what it's like to sit and check out VR. Netflix, Hulu, and recently Google's Play Movies services each offer something unique when you sit down to watch. You get a fun viewing environment to look around and interact with, an active VR menu for picking what you want to watch, and some clever visual tricks when the video starts to help draw you in to what you are watching.
HBO's VR app offers exactly none of these things and instead serves as an example of what minimum effort just so a company can say "we did a VR thing yay us" looks like.
Logging in shouldn't be complicated
One of the big things Google made sure existed for every Daydream developer from day one is the Daydream Keyboard. This is a VR keyboard every developer has access to so users can type with the Daydream controller. You don't do a lot of typing in VR, so this keyboard basically exists so developers have an easy way to let users log in to their services without taking the VR headset off. Instead of using this keyboard, HBO VR has you tap the app icon to launch the app, put the headset on, select a video to play, and as soon as the video is about to start you're asked to remove the headset so you can sign in to your HBO account.
There is nothing worse for a VR experience than being told to step out of VR as soon as you put the headset on so you can complete some mindless task that could easily be completed in VR. It doesn't help that HBO VR is a separate app from HBO Now and HBO Go, which already has your login credentials if you have it installed on your phone. Instead, this is a separate app with a separate login and zero respect for the user experience while you pull the phone out only to put it right back seconds later.
Welcome to the HBO bunker?
The virtual space HBO chose for their VR app is odd. You're seated in the second row of a two-row theater that looks like it could double as a panic room. The dark wood panel and brown leather seats are enough to give you a sense of depth, so it works. You can see details like input panels on the walls that help encourage that sense of realism that makes this kind of experience worth it in the first place, but once you are acclimated to this weird little room the rest of the experience falls flat.
Attention to detail does wonders for immersion, and HBO offers exactly zero of it.
Instead of a unique VR menu, the blank space on the wall in front of you that is supposed to be a large television fills with the Android app in tablet mode. There's a menu button in the top left, and you swipe around with the Daydream controller to access more than what you can initially see. A pointer shows up on the screen when you aim with your controller, but you can't use it for navigation. It's only for selection because you're basically using a giant tablet and not an interactive VR app. That means not only is it not optimized for VR use, but it's somehow even slower than the regular HBO apps for Android. Have you ever sat in a dimly lit theater wondering why the film hasn't started yet because nothing is happening on the screen? HBO recreated that for you in VR.
When you select a show or movie and it starts playing, nothing about the VR environment changes. To put this into perspective, Netflix and Hulu and Google are all set up to dim the virtual lights and give focus to the video in front of you. Netflix even goes so far as to animate the virtual light coming from the television, so you can glance down and see light reflections dance off of the coffee cup in front of you as though you were in a real place. This attention to detail does wonders for immersion, and HBO offers exactly zero of it.
Seriously, do better
The only upside to using this is access to HBO's content, which will eventually include unique VR video but right now does not. If you're already paying for HBO in one form or another this might be worth checking out to say you could, but the experience right now is just plain not good. Nothing about this apps feels like it was made for people to enjoy HBO in a new way.
It feels like someone at HBO said "hey we should have a VR app" and handed the job off to an intern. Considering how publicly Google promoted this app as one of the big unique things coming to Daydream, it's deeply unfortunate and could potentially ruin VR for someone who chooses this as one of their first experiences.