LD50 Version 1.2 has been submitted to Apple. The very brief release notes:
Added local head-to-head mode: 2 players can now play against each other on the same device!
That's right... local multiplayer... which means two human players on the same iPhone/iPod touch. Network multiplayer is being investigated for release with iPhone OS 3.0.
Also, the team at 148Apps.com was nice enough to do a review of LD50: