I understand that Flash, and animation in general is a notoriously difficult art to master for a lot of people, and not many people have the time, energy, or motivation to produce masterpieces, but this movie leaves a lot to be desired, to put it nicely. You wrote a story that could serve as a good brainstorm, a proof-of-concept for the animation, but it feels all concept, and no content.
There are a lot of issues. A lot. There are no sound effects, so it's hard to keep track of Reggie and the Beedrill's fight, and it makes the Viridian Forest feel lifeless. The choppy animation and lack of movement (Reggie and the Beedrill are just translating across the screen) also makes it hard to understand what the characters are doing or how they are interacting with each other, and as a result, the fight looks unfinished and unrealistic. Another problem is pacing: everything is going too fast for the small amount of scenes and camera angles, and I had to rewatch it multiple times to comprehend the story. Show, don't tell, as some people have said below...
These are some of the main principles of animation, which you should consider studying (I recommend Alan Becker's video on them) before all else. It's difficult for the audience to understand or even care about what is happening in your story without. You need to put more time into making this more full-on. You have the idea, just put your mind to and work on it, maybe see some example Movies here, you might be surprised by what you make :)