You will find whilst there can be some overlapping skills...there is a great deal of difference in these two roles.
Given my particular skill set, which includes a great deal of sense for gameplay balance that has helped me craft a number of tabletop systems, I would likely be better as a game designer than a writer. I was never truly happy as a writer because the worlds I created just weren't communicated properly through words alone. I always felt they needed to be seen, and I had a hard time getting across the more visual aspects of events as they played out in my head. A visual, and especially interactive, medium will allow for much more exploration of the settings and characters I like to write than a book.
From the perspective of your writing it is difficult without seeing examples of it to truly make any appropriately relevant comments with regards to your style, delivery etc. All I can do is provide some generic advice.
Given that I've had a hard time keeping my work recently, usually throwing it away because a change I make in the setting has made it non-canon, it's hard to find a good example now. I don't think any story I've ever written has remained canon for more than a year, and I throw out non-canon work so I don't get confused.
Were any of these stories published? As a writer if your stories are only seen by your initial surrounds i.e. school, family and friends you may not be receiving appropriate advice that will strengthen your writing rather what you effectively receive is feedback from a limited population pool that most likely falls into the same socio-economic and geographical pool and thus will have similar responses for the most part which may or may not be valid for a much larger audience....for example the work's of Jules Verne may not be to many people's tastes but in the larger population pool he is considered a great writer by many. If you haven't been, you should be dispatching your short stories off to the various magazines, competitions, editors in order to start garnering feedback as well establishing a portfolio for yourself (just take into account that rejection does not automatically imply a poorly crafted story). Do you belong to any writing organisations in your area/region/country/internet that affords you access to others who write, who have the advantage of also providing feedback as well creating the beginnings of a network of contacts that will serve you in a future career associated with writing.
Reviewers have included:
1. Yes, friends and family. They're convenient.
2. Other writers I've met on the internet.
3. Random internet blokes with no writing background.
4. English teachers, as I've been writing since middle school.
Of these, a family member proved the most valuable. She gave detailed and meaningful feedback in a way neither the friends nor random internet blokes nor other family members were, and she wasn't as transient as the other writers or English teachers. Unfortunately, none of the work she's read is still canon. (Rather sad, actually. It hasn't even been that long, and all of those stories are excised from the setting. I really need to find a version I like and stop changing it so damned much.)
If you are writing for games a good example of a typical situation you might face is that shown by Project Divine Thread, in this case you have no control over the initial ideas, the gameplay, the environment rather you are given the task of weaving all of these elements together to provide a plotline that works within the boundaries they have already established. Elements such as where the protagonist finds that they are a child of one of the gods is probably negotiable but learning to work with other people's ideas and having the skill to push for modifications to some of their thoughts is a tricksome process, at times requiring you to have the courage to speak up but also the wisdom to step back when our suggestion gets shot down in flames.
I'm the kind of person who prefers to have at least a vague outline of everything ready before anybody starts working. I've been on modding teams before, I know how this can happen at least in that context. Back in my pre and early teens I worked with a modding team that had a tendency to just keep adding more... and more... and more... until eventually we just couldn't get all the features (working features, mind you) to function properly together (my best efforts were in vain, as the moment it was all balanced they'd add something new) and the whole project fell apart. While with them, I was once in charge of writing a plot for a series of Halo: Custom Edition story maps, but every time I'd get a good draft I could run with the artist would make something new that just had to be added in or just had to have plot significance. (Nothing against the team, I wish I still knew them. But two of them died, then I moved and lost contact with the remainder.)
Maria: "Hey Jeremy, check it out! I made a seraph! We need a mission around them!"
Myself: "But there's no point in the plot where our characters will have access to spacecraft, or even high-altitude aircraft. When could they possibly come up against seraphs?"
Maria: "I don't know, just throw something in. You're the writer."
I really can't comment about your zephyr-like versus chainsaw to the head delivery of morality/commentary issues in your writing as I would need to read some of your work in order to make a judgement for myself as to how I perceive your delivery.
Tom was very right in pointing out that recognising your weaknesses in writing is a very good thing...my only caution to this is make sure what you have identified as weaknesses are in actual fact so. Hence the need to ensure feedback you receive is from a variety of sources. With specific reference to your humour in writing, you can not make everyone laugh...it just doesn't happen. There will always be some people who find humour in some things that other will define as sick...don't take it to heart and don't consider reader who can't accept your humour as being soft...just simply recognise that the type of story you are writing is the type of story they would never buy anyway i.e. not your target audience..:learning to write humour outside of your normal comfort zone is simply another skill and can be developed if you wish to.
My works are mostly serious, but the humour is either used to help define the setting or character, or else to help keep interest in the slower parts of a story. I think it's actually a bit more important because it acts to reinforce drama and isn't just for its own sake.
From a game designer's perspective. This is where you go through the game design forum as it doesn't directly relate to the writing forum except in the smallest part.