Haha Bloons is such a classic. Also just gave your game another try after your comment. Not sure if to edit the original comment with my new learnings but I'll just write it here!
I think I understand how actions work now: You gain 3 actions per day, but picking a card costs two actions - which explains why I could sometimes upgrade and sometimes could not.
I think it may need to be clearer conveyed that cards cost action points that also can be spent on upgrades. The moment I realised that I was like "ahh, now I get it. I can choose to place a new building, or get upgrades", and then it opens up a new way to play! It makes the game a lot more strategic and opens up more avenues on how I can spend my points! This game is actually pretty strategic, which is cool, it just needs to be clearer that's all.
I also tried the bowling alley. I couldn't unlock the later upgrades. I think they cost more action points? If so, I think it would've been nice to include the cost below the upgrade name as you have a text placement for a Description it seems. Also I'm not sure if I can do it but it would be nice to save up Action Points to rollover if indeed the upgrades can cost multiple points. I had one point and couldn't seem to spend it. I did manage to unlock up to the third upgrade before the square one for the bowling alley, and boy I think the bowling alley is my favourite now! I just love the way it bounces and gets bigger, and it can even push enemies in addition to damaging the little annoying flying critters that are unfortunate enough to be in its exact path as it lands? WOW! XD
After I learnt from your other comment that I can rotate buildings, it also made my second attempt a lot more fun as previously I had all my buildings facing the right haha, and so my left was pretty much undefended. I made it further this time and it was also a lot more fun for me!
Your team should definitely be happy and proud of what you've made!