"I started this project during Ludum Dare last weekend and seen your competition so I decided to do both. If that's OK"
Of course it's okay. As long as your project was created after the theme was revealed (which was around March 25th... 3 weeks before the submission opened), it's okay. I'm pretty lax with the jam rule so unless it's extremely problematic you are good
(Though I did remove the "first" submission to this jam, for submitting a paid game when the rule clearly stated the game has to be free upon submission... that and the fact that the game being submitted was three-year-old)