Has anyone done the Jackpot Buffalo Slots offer? Currently paying $80 for getting to level 91.

I came across this game a few nights ago when looking for a new slot machine offer to do. I did a search and couldn't find anyone that has posted about it, and there are only a few app store reviews, so maybe it's a newer one?

Has anyone else tried to do this offer recently? The first night I downloaded it, I got to level 30 or something very quickly. Now, the past couple days, I'm leveling up verrrrrrry slowly. I don't even understand the leveling up process, because it doesn't show any sort of progress bar anywhere that I've seen. I'm currently at level 45 and was spinning for 10+ hours today and didn't go up a single level.

I haven't had to spend any money yet, and the slots don't drain coins super quickly which is a positive, but if leveling up is this difficult now, I'm not sure it's worth continuing.