It's a very simple yet fun Gravekeeper's deck. It's not the most effective variant, admittedly, but I love the archetype and wanted to make a deck using only Gravekeeper's as main deck monsters.
The general strategy is to get Visionary and Supernaturalist on the board as fast as you can in order to secure a strong board presence. This is usually done with Dark Renewal on a throw-away like Recruiter, or using Spiritualist through either Monster Reborn, Headman, Throne, or anything in-between. There is also a good line-up of Xyz and Link monsters that help in a win more or comeback situation, like Lightning and Skull Dread.
The most obscure choices are just personal preferences I have either due to nostalgia or just generally liking the card. I can swear to you right now that if a deck has at least 2 level 4 monsters in it, you can be damn sure I'm going to put Cowboy in my extra deck. Always.
The side deck is mainly just for the hell of it. Mind Crush, Seven Tools, and Dark Bribe are favorites from my early days of Yugioh and I love using them as Side Deck filler. It is a casual deck after all.