I just released the new bugfix version (3.2.4) which fixes the following bugs (all of them reported by Keith):
- Repel touches were off in big simulation area mode.
- Zooming multitouch acted as a single touch when first finger was lifted.
- Particles got stuck on wall ends.
- Additionally, the maximum number of walls has been increased from ten to fifteen.
As usual, you can download it from the Google Play Store.