well... it doesn't really give me any tense vibes, in fact it kinda sounds happy at times.
my main grip is that it doesn't really sound focused, and many sections sound like notes were thrown at random, which makes for a very dissonant result. i don't really have a specific example of these, it's the track as a whole. dissonance is a very common and practical technique for creating a tense atmosphere if done right, but here it just sounds a bit ugly, and i feel like all the dissonance you have here is not really intentional or deliberate. i hope this doesn't discourage you, but i genuinely feel this needs a lot of work.