This plugin when published as main Captcha plugin is able to
- randomly rotate other Captcha plugins
- check visitors IP address against Blacklists (StopForumSpam.com, SpamHaus.org, Sorbs.net, SpamCop.net, UceProtect.net, DroneBl.org, BotScout.com, Project HoneyPot, manually defined blacklist of IPs or IPs range)
- check registered user email address against Blacklists (StopForumSpam.com, BotScout.com)
- check submitted content not to contain links, PHP, JavaScript or HTML
- check submitted content against list of whitelisted / blacklisted character sets (like latin, cyrilic, greek etc...)
- check submitted content against words and regular expression blacklist
- check submitted content against Akismet API
- detect language of submitted content by internal function or by DetectLanguage.com API and check it against language Blacklist / Whitelist
- detect continent and country (GeoIp) of visitor by internal PHP functions (if allowed), MaxMind.com api (free GeoLite2 or paid GeoIP2) or by StopForumSpoam.com API and check it against countries / continents whitelist / blacklist
- add additional check to submissions by checking Cookies support and Javascript support
- adds hidden field for users, but visible to robots (HoneyPot)
- checks minimal time to fill the form
- whitelist localhost / private networks / IPs or IPs ranges defined in settings, so no Captcha is displayed at all

All these are optional and canbe set / finetuned in plugin settings. All blocked submissions could be also logged, so you can give your users feedback, if their submission is for some reason blocked.