The product: The accessibility is key. Telling people to "scan the QR code" is great for getting it going.
The games: They're great. I love the variety and creativity. One problem is I had friends saying "They hate 75% of the games", and I don't know how you fix that - The games some players hate, other players _love_. But as someone who used to be in the game industry, I can promise you trying to make a game nobody hates is how you end up with bland flavor. Please don't end up there.
The lag: I don't know what it is - are the channels backlogged or what - But I would say 20-30% of devices are _unplayable_. It's not like the inputs are delayed, it's that they're fully unpredictable about whether they will register (and for how long). Same browsers, same Android OEM, same Wifi network and just... lag. The game says 1000ms+, but even when it says 200 it's laggy. This is probably your biggest issue, since in a 5 player party game, 1 or 2 people not having fun kills the mood.