According to NK blog you should only get forced ads if you haven't been watching the rewarded ones for a while. If you have and you're still getting forced ads, then you should probably report it to NK support. I'm not getting any forced ads, but I do use the rewarded ones every now and then.
Thank you! I'm so glad that the archive is available. May I suggest that your Forum page on NinjaKiwi.com should include a mention of that -- and possibly a lovely little screen shot of this Sub with a red circle around the "Archive Forums" link? I think it would really help.
Thanks!
There's an Android version of BTD 4 available for purchase here: https://www.amazon.com/Digital-Goldfish-Bloons-TD-4/dp/B007XKEXDK
To my knowledge it doesn't work unless you also have the Amazon app store app installed, so I don't think the APK alone would be useful.