Partial translation from Professor of mmcafe:
"According to reports, Dimps is location testing Rumblefish 2 for the NesicaLive in Akihabara Hey starting yesterday. Its balance has been tweaked. An official announcement should be coming today or somewhere very soon. No word on a console port although that wouldn’t be too hard to imagine.
- screen ratio seems to be the same 4:3 as the original. Moves lists are on the side.
- It’s Nesica card compliant, meaning player data can be saved
- Survival and Time attack mode can be played using the same input code as the original game (the command is displayed on the screen for convenience’s sake)
- Fonts used in the victory and intermission scenes have been changed
- There’s a loading screen and tutorial with a new female character illustration (probably a Probe-Nexus worker)
- The bosses are unlocked by default
- The graphical hit effects look more larger/dynamic now
- The character’s shadows look more blurry than before
- After the 4th match, there’s a fanservice cutscene that happens by tilting the joystick, at least with Garnet"
So it is indeed a re-release of TRF2, though with minor updates and on a new platform.