As of the most recent beta (beta 19), if you use the TWO theme, or a descendent of the two theme, then the entire game will be capitalized whether or not your print messages are capitalized or not. No need to manually capitalize your print messages.
To override this setting (you only need to do this if you DO NOT WANT allcaps:
start_theme = my_theme
// Your game code here
themes {
my_theme : theme {
// Inherit all the settings from the TWO theme
extends = two
theme_settings {
capitalization = original | upper | lower | camel
}
}
}