@Szilárd
SmileBASIC is a full on programming language, which you can use to make games, tools, etc. As I said before, the possibilities are endless! You can even MAKE a game engine using it!
There's a lot of things you can do in SmileBASIC. The possibilities are endless! If you want to download some programs, visit SmileBASIC Source (an unofficial place for posting public keys and forums). Here's the link: (http://smilebasicsource.com). Feel free to discuss your thoughts about SmileBASIC in the community (or on this discussion). Enjoy!
I forgot to say this earlier, but you'll also need to download the PetitModem program for PC too (just search "PetitModem", it'll probably come up as one of the first results). I'd also recommend buying a splitter for smoother transferring. You should get this one (https://www.amazon.com/gp/aw/d/B006T65CXE/ref=psdcmw_2267280011_t1_B00IX17RZY), as it's the most recommended splitter for PetitModem.
Mostly compatibility ones with the Wii U version. There's also a bunch of bug fixes. For reference: (http://smilebasic.com/debug/) (you'll need to translate the page, though).
Whoops, should've been more specific. I meant the Christmas Pack. I wanted to try out your old games, but I didn't download them when they were available, so I missed out. Save_Christmas is pretty awesome though, and I'm looking forward to another pack containing the old games!