Why is it that every time I enter virtual reality zombies show up? No matter; I shoot them down with my gun and start walking toward a monster in the corner. A beeping noise starts. What is that?

A disembodied voice gently reminds me that I am very near the wall. A real wall that will not yield if I keep walking forward.

It happens a lot in virtual reality. You forget that you are in a real room and not actually holding a giant zombie-killing gun. What was unusual about this incident was that I was not staring at Oculus‘ gorgeous high definition Rift screen. I was in a virtual world displayed on a mobile phone that hovered just an inch or two in front of my eyes.

Kits for turning mobile phones into virtual reality headsets have been cropping up on crowdfunding sites for months now, and news broke last week that Samsung is building its own. They work in generally the same way as units with dedicated screens: The viewer is presented with two side-by-side images that are almost exactly the same, save for the slight alterations that would come from the location of each eye. Users download an app to their phone and then just load it up before slipping the phone into their headset. The phone’s accelerometer and other sensors can be paired with accessories to create realistic head tracking and interactivity.

But no matter what the pitch, I was highly skeptical. Surely virtual reality requires highly specialized screens and electronics that a mobile phone can’t match.

That impression completely changed at last week’s Augmented World Expo. I tried prototypes from Sulon and VRelia, both of which relied on mobile phones for their screen. I rode a rollercoaster and toured a house with the VRelia GO headset and tried out the Sulon Cortex’s unusual combination of virtual and augmented reality.

They were surprisingly capable. Sure, the picture wasn’t quite as sharp as in Oculus Rift, but the headsets did the important part: They tricked my brain into feeling like what I was seeing was real. It turns out that you don’t need a super-crisp, life-like picture to feel totally immersed in a virtual world.

There was always going to be an ecosystem of virtual reality headsets. For those who want to spend $50 to$100 to jump into virtual reality, and likely far less in the near future, there are already some great options.