The best way to save RAM is to use small objects that get reused, or tiled. It has also been said that using lots of objects is bad for performance. If you're using small objects, you're going to need a lot more of them to fill out a level.
So which is worse? Huge tiles, or tons of small ones?
I'm not confidently clear on how to really, truly optimize a game. Is it really just a balance between RAM and processing? Are there any general guidelines or methods that take both RAM and processor usage into account, equally?
Also, why does a tiled object count as 1 object, but particle effects count as hundreds of objects?
Edit: I assume all instances count as individual objects?
I could really use some more clarity, overall.