Almost worth it – Proton Pulse for Google Cardboard Review

Not to be cheap but $2 is probably more reasonable. The view drifting forces you to slowly spin in a circle while you're playing to stay centered, which eventually makes you dizzy. Nonetheless the game changes enough to not be monotonous and is fun for 15 minutes or so at a time.
Review by Elivance on Proton Pulse for Google Cardboard.