This post marks the halfway point of the list.
Star Ocean: Blue Sphere
This is a surprisingly fully-featured JRPG that only ever came out in Japan. I was playing a translation patch that supposedly came from an unused professional translation that Enix commissioned many years ago, but the English text leaves a lot to be desired. Alas.
Its strongest point is the combat, which takes place in real time on a 2D plane. You control one of your three party characters and can switch between them at any time with select. Pressing A and a directional button is vaguely correlated to using specific moves, and special moves/spells are mapped to B and directions. It feels a bit like a fighting game, and it works great except that some enemy damage ranges from being unable to hurt you to practically OHKO with no warning. Even more bizarrely, despite leveling up the protag to an absurd extent, I never got a second special move.
I was able to do that because Blue Sphere's EXP system works by giving the whole party a set amount of skill points after each battle. Those can then be assigned to one characters skills, which boost their stats and sometimes unlock new skills. After about 140 upgrades on Precis, she still had exactly the same moveset as when I started. Still, those upgrades had unlocked the ability to play minigames to craft new items, which is a cool twist I'd like to see in place of more lame "give me three sticks and a rock" systems.
If this game had been five hours long, I'd recommend it pretty strongly. Unfortunately, it's probably something more like 20, and that's just too much when the gameplay hasn't meaningfully changed after the quarter mark and there's hardly any story to speak of. It's very cool that they were able to make this on GBC, but its value in 2021 is only as a curiosity.
Space-Net: Cosmo Blue
Another one that I'm not sure why I put on the list. The concept seems cool - you're bouncing around between the seven planets of the Rainbow System and seemingly building up both a crew and your technology, but the combat is dreadful. I did one fight against a single enemy that lasted about 8 turns. You might think that sounds fine, but the problem is that this enemy only took three hits to kill - I was working with 37.5% accuracy. In case you think it was just a particularly evasive enemy, it managed one hit on me after seven tries. Combat in this game would probably make for a great Monty Python sketch, but it's not fun.
Scooby Doo: Classic Creep Capers
I put this one on the list mostly because I played it as a kid and enjoyed it back then, but my dislike of point-and-clicks has unsurprisingly won the day. It's just way too slow paced for my taste, although I did appreciate a few of the jokes in the intro cutscene. I was also impressed by how it lets you change characters freely and remembers actions you've taken previously as them. The door on the right in the screenshot above is open because Shaggy did that, but a lot of GBC games would just reset the entire level after each character change.
Return of the Ninja
A game that is unashamedly Ninja Gaiden, and which is probably as unforgiving as that famously brutal title. You have four health and can only rarely restore any of it, the maps are full of traps that are almost guaranteed to get you on your first try, and reaching zero HP kicks you all the way back to the main menu. There's a level select to make it slightly less punishing, but that's only a minor consolation since the levels can be pretty long on their own.
I might have pushed through this with save states if it felt more fair. As it is, while I like the art and love how it gives you ninja tools to expand your exploration options, it's clearly a game that would be an hour long if it wasn't designed to deliver cheap hits. That kind of design was stretching acceptability even back then.
A 2D fighting game where there are a handful of different robot models that can be customized with different parts. The parts seem to make characters converge towards one style rather than giving you a huge variety of different combinations to play with. The bigger issue, though, is that the parts cost $1000 at a minimum and fights reward you with paltry sums like $20. Grinding out enough money to buy parts against opponents who often already have them (and thus have a statistical advantage) just isn't fun. Neat idea, bad execution.
Current status of the list: (Good games are bolded, green means finished and orange means abandoned. Bold means a game I'd recommend today)
1. Alone in the Dark: The New Nightmare
2. Arle no Bouken: Mahou no Jewel
3. Bionic Commando: Elite Forces
4. Cannon Fodder
5. Cardcaptor Sakura: Tomoeda Shogakkou Daiundokai
7. Croc 2
8. Daiku no Gen-san: Kachikachi no Tonkachi ga Kachi
9. Dragon Warrior III
10. Frogger 2
11. Ganbare Goemon: Tengu-tou no Gyakushuu!
12. Golf Ou: The King of Golf
13. John Romero's Daikatana
14. Kakurenbou Battle Monster Tactics
15. Keitai Denju Telefang
16. The Legend of Zelda: Link's Awakening DX
17. The Legend of Zelda: Oracle of Ages
18. The Legend of Zelda: Oracle of Seasons
19. LEGO Island 2: The Brickster's Revenge
20. Magi Nation
21. Mario Golf
22. Mario Tennis
23. Metal Gear Solid
25. Millennium Winter Sports
26. Mobile Golf
27. Monkey Puncher
28. Perfect Dark
29. Pokemon Crystal Version
30. Pokemon Card GB2 - GR Dan Sanjou!
31. Pokemon Puzzle Challenge
32. Pokemon Trading Card Game
33. Power Quest
34. Quest for Camelot
35. Return of the Ninja
36. Samurai Kid
37. Scooby Doo! Classic Creep Capers
38. SD Hiryuu no Ken EX
39. Shanghai Pocket
41. Shin Megami Tensei Devil Children: Aka no Shou
42. Space-Net: Cosmo Blue
43. Star Ocean: Blue Sphere
44. Survival Kids
45. V-Rally: Edition '99
46. Wacky Races
47. Wario Land II
48. Wario Land 3
49. Wendy: Every Witch Way
50. Xtreme Sports
Games remaining: 24