100% behind everything except points 2, 3. If it's not meant to teach anything then go nuts with 2 and 3 as well but if there's a goal then constant blinking, moving, flashing, glittering, jingling, spinning brightly coloured everything do nothing but distract from it.
for mindless tellytubbies stuff 2 and 3 are great. But if you want to teach anything then have *only the bit you want them to pay attention to* brightly coloured or moving or glittering.
I'd also add that anywhere you need to give instructions don't use text but rather have it speak instructions in a friendly adult voice. And most importantly praise. use that same voice for praise when the kid does something desirable in the game like solving a puzzle etc. Small kids love positive feedback, particularly being told they're doing something right.