Heres a few:
Legendary Axe for the Turbo Grafx - I always thought the first was much better than the second. I really like the first game.

Bubble Bobble - So this game has two sequels? Rainbow Islands the story of Bubble Bobble 2 and Bubble Bobble 2. I would say Bubble Bobble is better than Bubble Bobble 2 but maybe not better than Rainbow Islands. I like Rainbow Islands, its alot of fun once you get used to the controls. Parasol Stars is the story of Bubble Bobble III and thats an excellent game, I think much better than bubble bobble. We also have Bubble Symphony, which Im not a huge fan of. For a game with 'Symphony' in the name the music isnt all that great.

Maniac Mansion - I have never played day of the tentacle, but I would be surprised if it was better than the first. Got the 1st one on Nintendo for Christmas as a kid and loved it. Such an awesome game, where else can you nuke up a hamster burrito??