Thanks for at great game, and great update with endless mode :)
I experienced that the game just stopped at lvl 122. I had a summon heavy build but it seemed to have worked fine on other floors and I don's see anything particular that happened to have triggered a complete freeze of the game (played it just in the browser).
The game was just frozen at this point and more attacks happened. It was still possible to click toggle buttons (2x speed, and pause, but they did not do anything). 
This was the comp, The first dog, was adapted with the bee keeper, the gate with summon 1/1 copy, and the last dog adapted with trigger all on death effects. (the remainder were just double stats)
If I remember correctly the time it froze it was only going through the first revive cycle, and in previous battles it had managed at least two. Of course it was slow looping trough all the dead bees at time, but this time it just completely stopped attacking. 