This term is a portmanteau derived from two beloved games that arrived on the Nintendo Entertainment System in the mid-1980s, Metroid and Castlevania, and is usually applied to 2D games in which the world is explorable in all directions (as opposed to classic platform games, in which you go from left to right). There are usually secret rooms and areas that can only be accessed once you've found some key or item later on, so players have to mentally map their progress and backtrack when necessary. In this way a good metroidvania world is like a story, with tension, foreshadowing, plants, payoffs and surprise reveals built into the very foundations. Try: Hollow Knight, Axiom Verge, Ori and the Blind Forest. One of the most popular indie game genres, the term roguelike comes from the 1980 game Rogue, originally developed by coders Michael Toy and Glenn Wichman.

We covered various feature engineering strategies for dealing with structured continuous numeric data in the previous article in this series. In this article, we will look at another type of structured data, which is discrete in nature and is popularly termed as categorical data. Dealing with numeric data is often easier than categorical data given that we do not have to deal with additional complexities of the semantics pertaining to each category value in any data attribute which is of a categorical type. We will use a hands-on approach to discuss several encoding schemes for dealing with categorical data and also a couple of popular techniques for dealing with large scale feature explosion, often known as the "curse of dimensionality". I'm sure by now you must realize the motivation and the importance of feature engineering, we do stress on the same in detail in'Part 1' of this series.