It'll compile to JVM bytecode. I believe it also compiles to Javascript (I'm not sure if this is still considered experimental — I haven't looked in a while), which is pretty cool. I think it used to also target the .NET CLI as an experiment, but I'm pretty sure that's no longer a goal.
The important thing for me was that it compiles to JVM bytecode that's compatible with Java 1.6, so the resulting code can all be converted to Dalvik fairly quickly. The main downside right now is that you have to heavily prune the Scala stdlib, since it's packed with tons of methods and dex has a 16-bit method limit[1] — and you will hit it if you don't prune it (using proguard or another tool of your choice).
The important thing for me was that it compiles to JVM bytecode that's compatible with Java 1.6, so the resulting code can all be converted to Dalvik fairly quickly. The main downside right now is that you have to heavily prune the Scala stdlib, since it's packed with tons of methods and dex has a 16-bit method limit[1] — and you will hit it if you don't prune it (using proguard or another tool of your choice).
[1]: https://code.google.com/p/android/issues/detail?id=7147#c6