This was lots of fun. I really enjoyed it and loved the art and overall visual design of the pixel art and old-school feel, plus the audio. I prefer arrow keys for movement but I managed to adapt and then found the controls very easy to use.
The AI was good and once I'd mastered the controls I didn't find the game difficult (a bit too easy, actually). However, I found it easier just to play straight games of knocking out your opponents rather than bothering to catch balls and resurrect your players so I thought the link to the jam theme was a bit tenuous. I actually preferred it when I only had one player left on my team as it reduced the visual distractions and made it easier for me to concentrate on aiming and hitting opponent players.
Overall I really enjoyed the game, though - a good, complete package and really enjoyable.
I'd love to see a post-jam version that has a bit more variety in the players, gameplay rules, and visual locations of the courts because it's fun and I'd like to have a reason to play for longer (and have games that last longer) and feel challenged.