There are quite a few amazing platformers on TG/PCE. I think we all think Shooters first on this system but after cleaning up my game closet last night, I realized my platformers titles have grown, and now I have more of them vs. shooters!
Some of my favs:
Dynasty Wars SCD (Tenchi o Warou) - played this capcom arcade as a kid big time!
Wonderboy I - awesome, i play the sh*t out of this thing.
Wonderboy 3 (aka Dragons Curse/Advanture Island in JP) - for most this is the best of the Wonderboy series (not for me though, I love #1).
Wonderboy 5 SCD (aka Dynastic Hero)
Tekahashi Yumeijin (NEw Advanture Island)
Cadash (yes it is awesome)
Altered Beast (I love this for historical reasons, even though the Sega/MD version is much better)
Ninja Spirit (one of my favs!!)
Bonanza Brothers (not sure it counts as Platform, but it is a blast with the 2 player mode).
Dracula X SCD goes without saying
Downtown Nekketsu SCD! (River City Ransom)
lastly, Ninja Gaiden is awesome. The Hucard version is similar to the NES but with sharper graphics, and ability to choose to play in 3 languages (JP, English or Chinese!)