Here is what works for me:
Note: Hold down the Right-Alt key the entire time:
o Tab to get list of running apps.
o Pick the app to close, then Down arrow, then Space to actually close it.
o Repeat for other apps.
o When done, release right-alt key
I got a video projector a few months back that is running Android as a base OS, to which I attached a cheap wireless generic Windows keyboard. Projector is running some older version of Android. F3 also brings up the list of current apps, but it also seems to immediately context-switch to the selected app. The same happens when you Alt-Tab and don't hold down the Alt key. Hope this helps!