I'm also in the 8th dungeon of Oracle of Seasons. I played it while I was in Germany in June of 2013, but haven't touched it since. :/ Even worse, I tuned in to SGDQ in time to see them speedrun Link's awakening and Oracle of Seasons, so I couldn't watch constantly if I didn't want to get spoiled! :x
I have on and off period with Mario Tennis. My main character specializes in Speed and Placement, so while I have trouble with some of the special matches in the training courses, I smash everything else. I'm loaded with EXP since I completed nearly, if not, all of, the simulator challenges. I've hardly lost rounds in Campaign. I just need to play the game constantly, and not just in 1-week sessions every 5 months. XD I have yet to try a Mario Golf game. I will, eventually, though...
I played Metroid when I became an ambassador, and it was just a frustrating kind of hard that I didn't like. Unlike Zelda II, which is hard, but I like a lot. But I learned in the past year from multiple people that it was more than okay to dislike the game and call in blatantly bad in today's age, so now I haven't touched it in 2 years.
While you mentioned 3DS downloads, I might as well mention mine:
DSiWare:
Plants vs. Zombies
Cave Story
Tetris Party Live
Shantae: Risky's Revenge (which technically I own only on iOS because it was way cheaper)
Mario vs. Donkey Kong: Minis March Again
Zelda: Four Swords Anniversary Edition
WarioWare: Snapped! (which my sister transferred to me because she didn't want it any more)
Absolute Chess
Paid Applications:
Instrument Tuner (DSiWare)
Metronome (DSiWare)
Pokemon Bank/Pokemon Transporter
Pokedex 3D Pro
3DS Download-only's:
Pushmo
Crashmo
Mutant Mudds (<<<<<<AWESOME GAME!!!!)
HarmoKnight
VVVVVV (Also Awesome game that I bought only 2 weeks ago!)
Inazuma Eleven
Rusty's Real Deal Baseball (I currently own about half of the DLC)
Pokemon Dream Radar
Pokemon Battle Trozei (which I sort of regret getting...)
The Streetpass: Mii Plaza extra games
3DS games available in stores, but I bought them in the eShop because they were discounted and very rare to find:
BIT.TRIP SAGA
Shin Megami Tensei: Demon Souls: Overclocked
I've had a 3DS since Day 1, but my first 3DS game was Mario Kart 7. I didn't want anything else up to that point.