I ran a tearsheet on your result. Let's take a look at it.
First off, it still has pretty high beta. If you look at the rolling beta plot, it regularly goes well over .5. I suspect this is because you're not managing your beta so much as you are reacting to it.
Second is the position management. The "top 10 long positions" shows that it goes as much as 60-63% into SPY and TLT. That's a big exposure to a single name.
The third is probably the most important. When you look at the exposure chart you can see your algo is basically a long algo - it's always long the market as a whole, and is not well hedged. Of course, that's even more true given the underlying ETFs you've chosen!
You've got an interesting study. There are a lot of things you can learn from it. I recommend that one of the things you learn is to look at a bigger picture of how you can find a successful strategy, to take a step back from it and think about what your overall strategy is. Taking a mostly-long strategy and tuning it with some low-beta shorts isn't going to get you to a successful place on Quantopian. In the current set of contest rules it might (might!) get you a prize, but it won't get you an allocation. When we update our contest rules later this year, this won't be viable at all, even in the contest.
The material on this website is provided for informational purposes only and does not constitute an offer to sell, a solicitation to buy, or a recommendation or endorsement for any security or strategy, nor does it constitute an offer to provide investment advisory services by Quantopian. In addition, the material offers no opinion with respect to the suitability of any security or specific investment. No information contained herein should be regarded as a suggestion to engage in or refrain from any investment-related course of action as none of Quantopian nor any of its affiliates is undertaking to provide investment advice, act as an adviser to any plan or entity subject to the Employee Retirement Income Security Act of 1974, as amended, individual retirement account or individual retirement annuity, or give advice in a fiduciary capacity with respect to the materials presented herein. If you are an individual retirement or other investor, contact your financial advisor or other fiduciary unrelated to Quantopian about whether any given investment idea, strategy, product or service described herein may be appropriate for your circumstances. All investments involve risk, including loss of principal. Quantopian makes no guarantees as to the accuracy or completeness of the views expressed in the website. The views are subject to change, and may have become unreliable for various reasons, including changes in market conditions or economic circumstances.