A couple of updates from the ARMS Twitter account: first of all, they revealed another alternate costume, namely the dark-colored Ribbon Girl you see above. They also posted a screenshot of the “Arms Lab” stage as well as the next weapon showcase video, featuring the shocking Sparky:
電気のアーム「スパーキー」!
チャージすると、内部の発電装置があらわになるアブネー逸品!
リボンガールも愛用中で、身も心もシビれるパンチを放ちます!
旧型「サンダーパンチ」を改良した、最新モデルです。 pic.twitter.com/9Cl9CcHKq7
— ARMS(アームズ) (@ARMS_Cobutter) April 25, 2017
Here's also the alternate Ninjara which has already been revealed;