If Exile is too easy for you, try its sequel. Just prepare to invest in some Rogaine, because you
will be yanking your hair out.
I just played through CF2 again, spent 11 hours on it (I know exactly where I'm going at all times in the game so it's much quicker for me than for most). I never liked the combat system...in fact, when I was younger and couldn't sleep, I'd turn on CF2 and play a few battles...they are so boring that it would put me right to sleep.
Half of that is just in the fact that the game is so stripped down that there's no challenge in it.
The disc was designed very carefully...since they used the 64k system, and had to access a lot of graphics, all the regular music was kept on one track at the start of the disc (track 3 I believe) to reduce seek time by a great deal. The game does a lot of reading from the main data track (track 2) for simple stuff like character portraits and combat enemies. There's only so much you can stuff into 64k but it was a good example of how you can cheat a little. And I do agree that it seemed to be more of a tech demo than anything, just based on these details.
Ironically...I could never get into Yoshi's Island, or most any SNES game for that matter than came from Nintendo themselves. Third-party games sure, but not their in-house stuff.