Just a quick reminder for people who only read the play journals, and especially for people who want to share their programs. SmileBOOM has opened some discussions in with their official accounts. Have a look!
You can make your own sprites with the Smile Tool. By default, Smile Tool launches when you press the Smile button on the keyboard. If you save a sprite sheet that you made, you can load it in your program like so:
LOAD "GRP4:[File name]",0
Animation... I'm still figuring that out myself!
Defining your own sprites and animations isn't as scary as it seems at first. Take a look at BUB for some reasonably-clear examples: 83DXN3L4
Read up on the SPDEF and SPANIM commands; both have a variety of ways to define and animate sprites. My BUB game uses a DATA block to define them and inline SPANIM commands using "I" to determine which frame is shown for how long etc.