Thank you so much for the detailed feedback!
I actually added the +1 cards as a safety mechanic so the game wouldn't get stuck at "1" forever. The trade-off, though, is that matches can sometimes last a bit longer.
Reading your feedback gave me another idea. Instead of only changing the number directly, I could add cards that apply countdown effects over the next few turns. For example, a card that makes the bomb tick down by 1 each turn for a while, or one that doubles the next countdown effect. I think mechanics like that could make the endgame much more exciting, so I'd love to explore them in a future update.
I'm also planning to add checkpoints after the rating period ends so players don't have to replay the early rounds every time.
Thanks again for taking the time to write such a thoughtful review. I really appreciate it!