See, this is the crux. A lot of native speakers will drop the 'g' sound when they say words like 'running', 'walking', 'talking' etc. But this isn't a conscious choice, it just happens when you speak reasonably quickly in normal speech. Same as when something like 'want to' becomes more like 'wanna' when people are talking quickly.
A learner consciously trying to drop the 'g' sound in order to sound more natural will actually probably have the opposite effect, it will stand out as strange because it sounds forced.
King, spring definitely wrong. Perplexin would sound weird too.