It's 'no me gusta' - the pronoun stays with the verb and 'no' comes in front. As you have no idea of context in which this will be used, or whether 'the' would be required in that context, it's probably better to translate individual nouns with definite article literally, if possible, rather than guess on the possible usage.
It can be an emotional state or atmosphere.
For example: tension between two people who are angry at each other, but trying to be civil in public; tension "in the air" when contestants anxiously wait for the winners to be announced; etc.
There's a difference of nuance between tense and intense. Intense is something that's happening for / as a result of literally being "in tense" (having tension).
》I think of it like "tension gives birth to intense":
If you're being tense (have emotional tension), what you feel, say or do can end up being very intense.
Yeah, they are so close to each other! First I tried out of curiosity if this one would've been el tensión just to avoid confusion. No dice. :P
I'm in general good at hearing stuff wrong, so I really hope that recognizing these (and others like them) gets easier with time and practice. However, it might partially depend on how fast one is speaking and/or if they articulate properly, and my experience just has been 'fast and not so articulate'... o_O In actual conversations though, thank God there usually is a context, which maybe might help. xD
Duo lingo really needs to update so that in this, and other similar cases, the translation into English doesn't require an article to precede the noun. As a commenter below stated, a perfectly acceptable translation of "En general, no me gusta la tensión" is "in general, I don't like tension." There are MANY generalized nouns which carry an article in Spanish and explicitly omit them in English.
DL seems as a general rule to prefer the most direct, literal translation. Even though stress and tension mean the same thing (in certain contexts), there is clearly a more direct lineage between tension and tensión. Likewise, the MOST direct translation of stress into Spanish is "estrés" (where, again, the direct lineage is pretty obvious in the spelling).
If you were a simultaneous translator and your client used the word tensión and you, in turn, translated it as "stress", no one would fault you and nothing would likely be lost in translation. But I guess because DL is focused on the basics and the novice linguaphile, it tries to adhere to the literal, direct translation in most cases.