It is not great on many levels.
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It only runs against the Firefox user agent. This is not great as the user agent can easy be changed. It may work now but tomorrow that could all change.
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It doesn't measure load so even if your website has only a few people accessing it they will stick have to do the proof of work.
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The POW algorithm is not well designed and requires a lot of compute on the server which means that it could be used as a denial of service attack vector. It also uses sha256 which isn't optimized for a proof of work type calculation and can be brute forced pretty easily with hardware.
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I don't really care for the animé cat girl thing. This is more of a personal thing but I don't think it is appropriate.
In summary the Tor implementation is a lot better. I would love to see someone port it to the clearnet. I think this project was created by someone lacking experience which I find a bit concerning.