Don't be disheartened if the first demos don't do it for people. As mentioned before, the recording quality is something that needs to be spot-on for people to get that "wow effect". Luckily it's not very difficult to achieve: all you need is a decent microphone (preferably a large diagram one), a mixer/something with phantom power and a compatible sound card. They aren't that expensive, especially if you consider it an investment and a big step to becoming a voice actor!
I don't know how much you know, but there are many free softwares (like Audacity) that have great audio tools such as compressors that are a must to look into. For example, even with your present gear, you can make things sound much better with some basic 15-minutes-to-learn recording know-how.
The standards for all the game voice acting is insane these days, so definitely keep at it! It could also be worth listening to the demo reels of other VO people and learning how they do things and hone their voice. Perhaps even write them and ask for advice!
Hope you didn't find my tone condescending, it was more of a "thumbs up!"
Keep at it man!