Improvements include improved graphics, an "Advanced Mode," Japanese voice acting and "Very Sweet Mode"--where all ladies wear revealing outfits, Kotaku explains. Wii motion controls--including an obscene reload gesture--are naturally not directly ported.
Heroes Paradise is slated for release in Japan on February 25, 2010. Considering that No More Heroes was released worldwide by Ubisoft and sequel No More Heroes 2: Desperate Struggle is due to arrive in early 2010, a release elsewhere seems likely.
Thanks to Shacker valcan_s for the tip.