Can you recommend any classic games I haven't played yet?

[Zha Hong Lang]

Oh, I just remembered Sonic 3: Complete. It's a GIGANTIC hack that contains all sorts of QoL improvements to Sonic 3, I really recommend playing it if you can.

[PopYoshi]

NES:

Ducktales
Balloon Fight
Every Megaman game
Super Mario Bros
Fire Emblem Gaiden
Metroid
Mr. Game & Watch

SNES:

Street Fighter 2
Super Mario Allstars + Super Mario World
Zelda a link to the past
Super Mario Kart
Fire emblem (3, 4, 5)
Contra 3
SMW2 Yoshi's Island
Ghost N' Ghouls

NDS:

New Super Mario Bros
Mario Kart DS
Barnyard Blast
Advance Wars Dual Strike and Days of ruin
Contra 4
AOE: Age of Kings DS
Sonic Rush/Rush Adventure/colors
M&L Bowser's Inside Story

[zxcv]

Can I recommend hacks?

SMW:

- Drama Mistery
- Super Mario World: the after years

[Perunasose]

Well if you like Pokémon and RPGs, try Pokémon Mystery Dungeon games for DS. Very different compared to the main Pokémon games.
Also, am I blind or did you really miss SMB3?

[FireyPaperMario]

Have you try any of the Neo Geo games officially for the Neo Geo console? If so, I'd recommend World Heroes I & World Heroes II! ^^

[Snessy the duck]

Judging from the list, it seems like you haven't played the original MM4. I'd recommend doing that, it's actually really good despite the somewhat mixed reception it's gotten.

[Prismarine]

Maybe you should try the PC-98 version of E.V.O but since its mainly japanese, id recommend downloading the english translation right here.
What more i can recommend:
GBA

• Kirby & The Amazing Mirror
• Pokemon Mystery Dungeon 1

SNES

• Crono Trigger (greatly recommended if you never played it before)
• Sonic 4 (bootleg/hack? im not really sure)
• Pilotwings
• Simcity (my favorite)

DS

• Bomberman DS
• Pokemon Mystery Dungeon 2 (absolute masterpeice)