Cotton for the pc engine is an amazing port, a port i thought would not have been impossible if i hadn't played it.
The best way to explane it is to compare it to the closest thing on a rival system, cotton 100% for super famicom which has allot of the same effects and similar sprites, for example, where is a effect such as lightning, dragon or an explotion might have around 7, 8 and 5 frames in cotton 100%, there will around 22, 26 and 11 in cotton for the pc engine, as well as some of the sprites being far better animated and so on.
Its truly superb, infact you can make a comparison on how Dracula xx compares to Rondo, both pc engine games, both are Super Cd's and both Super Famicom games are 16 MB, which is huge for a rather short action game and a shooter although the cuts in Dracula xx animations, details and such are far, far worse.