I'll do be my best to help, although others will probably give far better and
more accurate advice.
(I) Personally, I would recommend Python due to its clean syntax, high-level
nature and wide support. Javascript is also pretty good on these fronts
(though its syntax is a little too brace-heavy, I personally think). However,
OnPon4's advice to use game engine (libre of course!) is far better than
choice of language, as it hides much of the dirty work from you.
(II) I'm no expert, but a few posts regarding the issue appear to suggest it
may be to do with the monitor (sources attached at end of section). Try
running "xrandr" (no quotes) at the command line and see if throws up some
sort of message like "xrandr: Failed to get size of gamma for output
default". If that's the case, you may need to set your monitor resolution
manually, which I believe is detailed in the first source below. Hopefully
someone else can be a little more helpful than I am in regards to this.
Source 1
Source 2
(III) I'm unable to assist here, except to point out that you probably meant
"capture" and not "caption". Sorry!
