Haha, it's always awesome how responsive you are with feedback. Even if you don't use it, hearing your perspective is something I really enjoy. More to the point, it helps me understand what your goals are.

To expand on some of what was said, the start screen doesn't need to be luxurious or pretty it just needs that "AWWW YEAH YOU GONNA PLAY A GAME NOW" factor. I suspect making a good title screen is trickier than it seems (kind of like business cards) but making an acceptable start screen may just be a matter of rearranging.

On progression, I'd say your points regarding your ability to tweak the curve are correct. There's not too much wiggle room. Given that, I'd suggest that you play with how the content is curved out. Personally, the biggest obstacle to me was the 2outof3 match format. It was fine in the beginning when the novelty was fresh, but later on it dragged on hard. Cutting it to one match per enemy would be amazing for my personal experience. Part of this is that the match format didn't feel like a match format. Content felt like levels not matches. When I won it felt like I had to repeat levels rather than beat an enemy twice in a row. Single matches would advance players through content quicker and feed into progress more clearly.

Honestly, it all comes down to keeping up motivation. So long as you do that, it's all good. My views on progress don't need to be addressed specifically, they're just a byproduct of losing motivation. Here's what I think would work:

• Ditch the 2 of 3 format. 1 match per enemy.
• If you want to preserve the flow of the 2 of 3 format, change the presentation of the matches. Instead of playing two-three matches, have 1 two-part match. Once people clear the first blocks, the opponent could react and summon a slightly more difficult set of blocks. They could also summon another obstacle or tennis ball. This is more interactive and the progression from clearing the level once is more obvious. The difficulty doesn't necessarily need to increase, but I think the enemies need to be interactive. Yup, I'm going full idea-fag here.
• Make matches feel like matches. It doesn't feel like you're squaring off against an opponent the second time around. Maybe be more obtrusive with the quote change.
• Improve score-keeping and screen transitions. I'm convinced that if you did an amazing job with this, none of the previous suggestions would be necessary. Problem is I have no idea how to do an amazing job with scorekeeping and transitions.
• You could beef up scorekeeping by introducing a timed element to beating matches (for pointkeeping purposes). Personally, I think that'd be dumb unless the speed increased the fewer blocks there are (a la swarm). Speeding up the ball as you destroyed blocks would also create a more obvious flow to matches.

Anyways, whatever you choose to do, I BELIEVE! Pyscho Tennis is gonna be so hype next time I see it!

I'll let you know when part2 is up. I don't have all that much left to say but by God i'm gonna finish this game!