Like the original game, I think Digidrive's learning curve may seem a bit steep in the beginning, but once you familiarize with all the mechanics the game becomes really addicting and I found mastering it very satisfying. Definitely one of the most complex and original Bit Generations/Art Style titles.
Overall I think I liked this DSiWare version more than the GBA original, because the dual screen makes everything more readable and thanks to the medal system you can always keep track of how many unlockables you got and in which mode.