I got an idea about electricity that would let you build, if you have the patience, functional electronic circuits at almost no CPU cost. Since pressure and explosions are being mostly irritating to implement without slowdowns, I think I'll add that first. Also, there's a version coming your way as I type this. No big visible changes, just some more speed =) (And the fire is hotter!)
@JonJin: Plastic Explosives :) @wolfbill: I'm more of a programmer, but I guess I could teach chemistry if I needed to. The ground melts with acid because of the calcite it contains. Also, it's a game. (Sort of)
@444red444: Having an undo button would be pretty expensive, as I'd have to save the world before each player intervention. I rather have a local save/load so you can save your progress without uploading it to Kongregate.
@Gabriel: I intend to add a drawable cooling element to the game (Other than Ice). With that and Fire, I don't see why people would need an artificial temperature change.
@animereviewdude: You can use W and S to change the brush size. I don't know any way to stop the browser from scrolling =( @zonata2: No, the fixes aren't on Kongregate yet.
@badad7: I've spent the afternoon implementing a system, but it's too slow for most PCs. I think I'll scale it down a lot =p @jb8salstead: Does it matter? :S @zonata2: Igneous rocks aren't necesarily metals. And yes, glass already stops acid in my code :)
@keyofdoor: Clouds would be fun to program. If only I had air pressure already implemented... @llloksd2: Most maps made before v0.68 won't work anymore. Kongregate doesn't have a way to eliminate shared content, sadly =(
Hey! Good news! I just finished implementing the "particles keeping data about themselves". This means sometime this week there could be a solution to the lava never cooling down and the almighty acid. Also, it brings a lot of new possibilities for the game and, while taking ~5 Mb more RAM, it reduces the CPU time by 10%. All in all, a big step for SandTest. Also, I believe that save files post v0.68 will be functional with the new schema.
jb8salstead: Nah, I'm pretty sure there are some other games with listening developers. It's just that SandTest is still learning to walk and takes advantage of every little advice. It's harder to add features to completed games. Still, I'm glad that the game has reached this stage, I never imagined having such a community working with me into improving the game ^^
@chefchaot: I know, acid should convert to something else after eating stuff, virus should have some rules against it's growth at least and lava should cool down after some time. For all of that, I would need particles to keep some data for themselves, which they aren't doing for now.
@Eldon101: I'm loving that idea =) Although what could be the possible interactions of an alkali? I don't want to have elements that have only one purpose.
Fire got cold somehow :S Ok, I'll fix it tomorrow :) @jb8salstead: Acid working with electricity to make batteries, I'd love to program that. I have some plans to implement something more complex that what dan ball does with circuits, but I'm working out the details. Air pressure system is on the todo list too =)
Nick: It takes some time (About 10 seconds) for heat to dissipate. lolzorlolz: There will be a time for the "boom system". I can only tell you it's a priority and the next time I have an entire afternoon to work in that, I will. (It's something you can't work on a couple of hours a day)
 "SandTest")