The good news is that version 2 was just released on the iOS App Store and it has all 8 playable characters that were originally planned.
The bad news is that Isis is missing visuals for one of her abilities, there are no sound effects for the abilities, and the UI is still temporary.
As for Mecha Drop's future, updates will now have a dramatically reduced feature set considering how long it took to come out with version 2.
Version 2.1
- Visuals for the second Isis ability.
- Improved UI, including tooltips for how to use each characters' abilities.
Version 2.2
- Multiplayer
Story Mode had to get cut, unfortunately. There will also most likely not be a version 3; version 2.2 will probably be the last big release.
Sorry to disappoint, Mecha Drop fans, and thanks for waiting. I hope you enjoy version 2!