Oh, you can put ads in your game, even annoying ones. My concern is only the homebrew phoning home aspect you mentioned. Just as with AI art, there are people that will take issues with that, including downvoting your game and leaving bad comments or reviews.
Unless you have compelling reasons, maybe consider if a static promotion build would achieve your promotion goal just as well. You have a title screen and a short period between levels, more than enough time and space to put the promotion.
I get you. When I first put the game out, I did get a number of bad reviews both from the in-game ads, and from the fact that webgl is kind of... inconstant.
But I do want to be able to promote any of my games from any of my games. I guess some people will freak out.
Anyway, I put an option in the menu that let's you turn off promotions(downloading them too), and I inform the user that that option exists when they hover-over the "boost" icon. And I still give them a set 10% boost if they opt-out, as opposed to 35% for looking at it.
The scary thing about Kongregate was that there were people down-voting any new game that looked decent with about 10 accounts. I think the prize money for their monthly contests was bringing out the worst in people.
