What is Chess Ultra?
Chess Ultra is a piece of chess software. Feature-wise it's pretty bare-bones, it doesn't have much in the way of game analysis, strategy information, application configuration, etcetera. Its main selling point is its graphics; graphically, it is beautiful. It is available on Steam, the Microsoft store, and various consoles such as the Xbox One, PS4, and Nintendo Switch. I can't speak for the graphics on console systems, though; they could have lower graphical settings than the PC version would allow at high-level settings.
Features of the software
The primary feature of the software is the ability to choose between multiple piece sets, change the materials that the sets are made out of (multiple wood options, metal options, stone options, et cetera), and choose the board and background location that you are playing at. Without any DLC, the game offers four chess sets. There are ten DLC chess sets available, including one Ancient Roman/Greek set and an Easter Island set, among others. Many of the DLC sets come with their own board/location as well. One of the chess sets that come with the game is gargoyle/imp themed, with the location "Gomorrah", which is a bleak, esoteric ruin. Other locations include a manor with a crackling fireplace, a museum with Greek sculptures in the background, and a table with a book and a plant on it. You can play any chess set and material with any location; however, each location's lighting has a color-scheme. Although your material has its own colors, the lighting of the location will to some degree affect the color-scheme of the pieces. The lighting reflects off the board and pieces based on your camera angle, which is a nice touch. Each location has its own collection of soundtracks that match the general mood/ambience of the location.
The software has various play modes, the first of which is against a chess engine. The game does not specify which engine; my assumption is that it is an open-source engine, but it could be a chess engine designed specifically for the game. There are ten difficulty settings, and the engine has an estimated ELO rating for each difficulty. The ELO rating for the engine's difficulty setting changes based on whether you win or lose a game against it, which I personally find to be frustrating. The other play modes are local hotseat games on the system, online play, friends-list, and "recent", which is people you have recently played against. When setting up games, you can set the timer to blitz, standard, marathon, and Fischer.
There are various tutorials offered in the software, including basic gameplay, castling, en-passant, various checkmate strategies, various openings and tactics, notation, midgame, and endgame. There are also various puzzles offered in the software, including a number of mate in one puzzles, up to mate in seven, as well as "traditional" puzzles.
Tournaments are also a feature of the software. There are recurring official tournaments, as well as the ability to make your own tournaments. The official tournaments can have 64 players, while the tournaments that you make can have 4, 8, 16, or 32 players. You can choose to have the tournaments open to friends only, or open to anyone. Tournaments only offer blitz and standard timers.
The settings allow you to set your graphics to low, medium, or high, as well as configure your resolution, sound volume, music volume, HDR mode, and whether you want the game to show legal moves.
You can export the PGN from a game into a chess analysis software and analyze your games. This makes up for notation analysis.*
Subjective impressions
The graphics are gorgeous, and the soundtracks are amazing. I wish I could buy the official soundtrack, but unfortunately that's not a DLC. The bot is fun to play against, but I personally prefer Lichess for all the features that it has. I would not use Chess Ultra to play online. I can't speak for the tournaments or tutorials as I have ignored them so far. The Steam version comes with achievements for accomplishing different things in the game. I am immensely bugged by the fact that the engine's ELO rating changes based on its game performance; its rating should be absolute per difficulty setting. There are other small things that tick me off with the software; right clicking a clickable element does not bring up options for that element, it is treated as a left click. In other chess software, I am used to left-clicking to move and right-clicking to de-select a piece, but left-clicking moves the piece in Chess Ultra. Because of this, I have made many accidental moves. There is no takeback option.
Another thing I highly dislike is the fact that there is absolutely no notation display**. In most chess software, a list of all the moves will be notated in chronological order to the side of the board, usually the right-hand side. (Lucas Chess being one example, as well as almost any paid chess analysis software such as Komodo, Chessbase, Fritz, Chessmaster games, and online software such as Chess.com and Lichess.) The A-H ranks and 1-8 files are correctly numbered on the board, but I don't think it would be all that difficult to include in the software. Marketing the game as "minimalistic" is simply an excuse for being lazy; they had ought to include notation and make it optional from the settings for people that want "minimalism".
Is it worth $13? Subjectively, I'd say no. I tend to appreciate analysis features a lot more than I appreciate graphics (though I do like a well-polished looking GUI). If you think you're going to play it enough to get your money's worth, go ahead and buy it. The only reason I can fathom buying it is if you appreciate graphics more than features. If you don't particularly care about the graphics or couldn't run it on your system, don't bother getting it.
*You can export PGN files at any time during a game against the bot, but I am not sure if you can for games you play against other players.
**There is a limited notation display in which it displays the moves on each side of the board for each player, but not a proper notation analysis display